Participants were recruited through the research group's social media and a specialist headache outpatient clinic using a purposeful sampling strategy, concretely the Criterion Sampling Technique26. This technique is used when the research seeks to include all cases that meet a predetermined criterion26. The study included individuals of both sexes, aged between 18 and 55, diagnosed with migraine according to the 3rd edition of the International Headache Classification1, with at least one day of migraine attack per month. Participants had to report NP at least twice a month for at least three months. The association between the conditions was based on self-report. Individuals with other primary or secondary headaches, a history of trauma to the face or neck, a history of cervical disc herniation or cervical osteoarthritis and any systemic degenerative disease were excluded. All participants had experienced physical therapy and/or pharmacological treatments at some point.

There are different proposals for estimating sample size in qualitative research (pragmatic considerations, saturation, power of information, etc.)27, as there is no previous formula for calculating it26. Previous studies using empirical tests determined the number of interviews necessary to achieve saturation28–31. A concept saturation proposal by Turner-Bowker et al32. based on empirical test was applied. It describes that 99.3% of concepts, themes, and contents emerged with around 25 interviews. With this proposal, a greater capacity to identify codes, categories, and topics is achieved. In addition, the current proposal also helps researchers to know a reference number to stop collecting data and/or recruiting participants. Finally, 27 participants were included. Two more were added to confirm that no new content emerged.

The researchers had no prior contact with the participants. Individual, semi-structured interviews26 were conducted by the researcher (MDDR). The main questions were: a) Tell me about your NP. How does it feel?, b) Could you describe what it feels like when you have NP?, c) What do you think NP is?, and d) What do you understand about what is happening when your neck hurts? During the interviews, the researchers noted the key words identified in the participants’ responses and used their answers to ask for them to clarify the content (e.g., "Please tell me more about it"). In addition, participants were encouraged to elaborate on their answers, which allowed for a more detailed exploration of their perspectives. The interviews were conducted face-to-face or via a private video chat room through Google Meet. Six participants were interviewed face-to- face, 20 preferred the online modality, and one participant had to split the interview into two parts, first online, and secondly face-to-face. The interviews lasted an average of 59 minutes (SD: 15.6). Field´s notes from researchers were used, such as secondary source of data, which provided in-depth information during data collection26.

Clinical and sociodemographic information (age, body mass index, sex, race, marital status, education, occupation) and characteristics about their headache and NP (diagnosis, Neck Disability Index, Headache Impact Test, frequency of NP and monthly headache attacks, duration of headaches in years) were collected.

All interviews were transcribed, and Miles et al33. analysis proposals´ based on Codebook Thematic Analysis28,34,35 was conducted. This analytical approach allows us to inductively identify, through several cycles of coding, the content relevant to participants in their narratives, categorize it using a codebook, and present it in a structured way, using matrices or other forms of visualization. The analysis process began by identifying the relevant text fragments that showed information that responded to the research objectives33. From this information, codes (descriptive content) were identified based on the participants' narratives. These codes were then grouped into categories according to their content. These categories were reviewed and grouped into themes, considering similar subjects that could correspond to the experiences reported. Table 1 shows an example of analysis process.

Two researchers (MDDR and JCSM) double-coded the analysis and held weekly meetings to discuss the data, presenting the final categories and themes. If there was a difference of opinion, a third researcher (DPC) and the team discussed to reach a consensus, ensuring triangulation of the researchers36. Excel was used to analyze the data, develop matrices, and make comparative tables of the analysis results.

To control trustworthiness, the criteria of Credibility, Transferability, Confiability and Reflexivity were followed36. See Table 2.

When describing their NP, characteristics such as stiffness, tension, heaviness, and locking emerged. One participant (P16) described the pain as something tangible, like a “brick.” Regarding its location, the trapezius region and the back of the neck were mentioned, and it could be bilateral for some and unilateral for others, whether or not related to the headache.

Regarding the NP during their daily routines, it was described as painful, very painful, uncomfortable, and bothersome. Some participants (P6, P17, P23) reported that they were less bothered by the NP compared to their headaches.

Furthermore, emotional states were reported by all participants. Anxiety, sadness, and frustration emerged when they did not perceive improvement, doubted their ability to manage the pain, or when pain persisted over time. In addition, they felt upset because they thought there was no solution to the tension in their neck and the discomfort. In addition, one participant stated, “I get upset because there’s no solution to stop this tension in my neck. It’s very painful” (P16).

Overall, these accounts indicate varying descriptions of NP among patients with migraine, underscoring both the subjectivity of the symptom and the lack of conceptual clarity. Moreover, it becomes evident that NP is not merely a physical sensation but also influences daily functioning and emotional well-being, highlighting the need for its consideration in clinical practice.

There were divergent views on what triggers NP. Some of the participants believed that there was a direct link between migraine attacks and NP, which could be triggered by headaches or vice versa. “Sometimes I feel the headache comes first, other times the neck pain. I can’t tell which one starts it” (P3). In contrast, others mainly attributed NP to posture and daily positioning, such as when sleeping, with mattress and pillows described as possible contributors. “I don’t allow anything that stresses my neck. I’m very careful with exercises that strain these muscles” (P4).

Emotional factors, particularly stress and anxiety, were also identified as triggers. Yet, some reported uncertainty, with one women stating, “I’m not really sure, maybe it’s the pillow or mattress, or something like that, but sometimes it comes with a headache and sometimes it comes on its own” (P20).

Two participants (P3, P20) who related their NP to migraine attacks had different opinions about the order of the factors in terms of what starts first (the NP or the migraine). Although some said they could see a relationship, they doubted which started first. On the other hand, two participants (P10, P15) began to associate NP with migraine after physical therapy sessions.

These accounts indicate that uncertainty about the true causes of NP was common. While a few participants connected it to migraine, many others attributed it to everyday factors such as tension, posture, or routine habits. This variation highlights how participants make sense of their experiences and illustrates the subjective, multifactorial nature of NP in the context of migraine.

During NP, the strategies included medication, exercise, posture care, and manual therapy. In times of severe pain, they use painkillers and muscle relaxants. Only one participant (P1) sought medical attention to understand the cause of their NP and the medical related emotions to muscle tension capable of generating NP.

Physical exercise appeared as the main prevention strategy for NP among the participants, such as moving the cervical region, stretching, and exercises guided by the physical therapist. However, three participants (P18, P19, P24) reported that exercise did not help, and one (P24) of them said that exercise could make her NP worse.

Regarding posture and manual care, the participants mentioned self-massage, ergonomic strategies during work, and the need to manipulate to feel relief.

Two participants (P4, P16) went to a physical therapist to treat their NP. One reported that they tried to loosen their muscles, but she said she was afraid of myofascial release and that the manipulation made her pain worse, leading to vomiting attacks. The other reported a good experience with manual therapy and the exercises aimed at the cervical region guided by the professional, noting an improvement. However, when NP is already present, most of the participants reported that they did not allow the pain to get in the way of their routines and that they carry on with their lives as normal, some even commented that they have gotten used to it or that they try to change the focus. Some answers show that if the pain were only in the neck and not in the head, they would cope and it would not affect their daily activities.

These reflections indicate that participants sought to adapt to NP to preserve their daily routines, often by shifting focus or normalizing the discomfort. One participant stated, “I just carry on with life as normal. I’ve gotten used to it” (P18). Such accounts suggest that, despite variability in the strategies employed, many participants framed NP as something manageable within everyday life, emphasizing continuity of functioning rather than disruption.

One case (P2) described how normalizing their pain within their family was a tool. Pain normalization consisted of family becoming aware of the need to take care, reminding them about their posture and ways that could help prevent NP triggered by their positioning. Also, making jokes concerning the alignment of their neck ("look at the crooked neck").

In addition to NP, the participants reported feelings of pain, and discomfort, as well as stiffness and tension, which could make it difficult to move. These symptoms were usually found in the trapezius, posterior cervical, and occipital regions, and they were not isolated. Headaches could be present. Previous studies on NP of unknown origin have also observed the same thing regarding its symptoms, in which NP does not appear alone but also with stiffness, tightness, and the sensation of blockage that could make it difficult to perform movements37–40.

Still, other studies that included individuals with NP without another associated diagnosis mentioned headaches, dizziness, visual disturbances, tinnitus, nausea, as well as sleep disturbances37–40. Like our study, in which all the participants had the same symptoms, these are part of the clinical characteristics of patients with migraine, and all our patients received a previous diagnosis when they took part in the interviews. It is, therefore, possible to visualize the complexity that NP can involve.

Neck pain causes frustration, anger, anxiety, insecurity, and depression41. Similarly, patients with migraine experience anxiety, anger, guilt, stigma, isolation, and depression7. The study's data supports these findings. ​ Participants also mentioned anxiety about future attacks and the belief that they will never improve. ​ Studies indicate that fear and anxiety about future pain can lead to greater disability and a distorted perception of pain42–44. Because it is known that the sensation of pain is an individual and subjective perception, emotional factors can influence physical conditions through greater perception of pain and increased sensitivity45. In addition, the belief that pain may persist can hinder the process of self-management and adherence to treatment43.

When it came to the causes of NP, opinions differed. Some believed that there was a direct link between migraine attacks and NP, which could be triggered by a headache or vice versa. It is already known the relationship between NP and migraine, as in a prospective study that showed that 70% of individuals with migraine has NP and stiffness14, which tends to appear before the attacks or right at the beginning of it1,13,15,46. However, it is still unclear whether cervical symptoms are actually premonitory to attacks or whether they act as triggers13,47, which is also a real doubt for patients who describe it.

Poor posture and stressful mental conditions can lead to increased tension in the neck muscles, causing and maintaining neck pain37,38,48. Participants in the study mentioned that they need to be mindful of their posture to avoid neck pain, which aligns with other studies showing a link between neck pain and migraine. Emotional factors like stress and anxiety are also identified as triggers for neck pain17.

Finally, emotional factors, especially stress, have been identified as a triggering factor for NP, corroborating other authors, who have shown that emotional elements, such as anxiety and stress, have also been identified as responsible for the onset of NP37,41,48.

One of our interviewees mentioned that when seeking treatment for her NP, techniques performed by physical therapists, such as myofascial release of trigger points and manipulation, were able to worsen their symptoms, with episodes of vomiting, and that certain exercises could also lead to worsening pain. This is in line with the study by Carvalho et al16, which found that part of their sample reported that treatments conducted by physical therapists, including trigger point therapy and exercises, could trigger migraine attacks. This can be justified, as NP is present in attacks. When certain techniques are performed during an installed attack, they can be less effective and even worsen the condition. When we think about the pathophysiology of the disease, which is related to central sensitization16,49. These responses are a warning sign to health professionals when assessing and treating this patient population.

Most participants found physical therapist-led exercises and stretching helpful for preventing neck pain. Manual therapy, especially self-massage, was also mentioned. A study by Carvalho et al16, had mixed results: some participants improved, some saw no change, and some had worse headaches.

Schultz et al17, on the other hand, followed the same line of results as ours, where participants reported that physical exercise, in general, was an important aspect of controlling the disease and that many patients seek treatment with physical therapists or chiropractors as prevention or after attacks. Stretching was also cited as a good strategy when the pain is related to muscle tension.

Our results show how pharmacological strategies were used in cases of more intense pain, such as analgesics and common muscle relaxants. Generally, non-pharmacological treatments may be a better option as they do not involve side or adverse effects50, and within this, some participants in another study claim to use medication only if stretching and relaxation exercises do not resolve, but for others medication is their first choice as a treatment17.

When NP presents on its own, it does not lead to changes in activities of daily living, despite being uncomfortable and difficult to deal with, and they are able to maintain them normally. Other studies have shown that patients with only NP of unknown origin have had to modify their work activities, being forced to take long periods of absence37–39,51.

We believe that the fact that most of our participants had low or no disability on the NDI may justify this difference with other published studies.

Concerning individuals diagnosed with migraine but who did not assess the presence of NP, participants reported that the pain ended up affecting their quality of life, leading to lower performance in work activities and difficulty in social activities8,52. Moreover, when NP and headache are associated, there is greater disability, lower productivity at work, depression, anxiety, and allodynia14. Corroborating the previous findings, the interviewees reported that whether the headache is present with NP has consequences for their quality of life regarding emotional, work, social, and economic aspects.

The participant describes the normality that her family brings to her condition and the awareness they have created about the need for her to take care of her neck. According to Kragting et al41, patient's perception of their pain can be influenced by their family members, and our participant mentioned that this care helped them to remember their posture and ways to prevent NP.