Background: There is evidence linking conditioned pain modulation (CPM) deficiency with musculoskeletal pain syndromes such as fibromyalgia, migraine, tension-type headaches and irritable bowel syndrome, as well as with temporomandibular disorders, idiopathic facial pain and chronic fatigue syndrome. Evidence shows that in pre-surgical situations of chronic pain there is no activation of CPM.

Objectives: The purpose of this study is to measure the CPM response and determine whether neural tensioner exercise in patients with chronic neck pain is effective in the improvement of neck pain intensity, neck disability and cervical range of motion.

Design: Double-blind, randomized placebo clinical trial. Methods: Patients with neck pain will be randomly allocated into two groups: the neural tensionner exercise group (NTE) or the sham technique (ST) group.

Individuals will be included in the study if they meet the following inclusion criteria: aged 18-65 years, neck pain perceived in the posterior region of the cervical spine, from the superior nuchal line to the first thoracic spinous process with more than 12 weeks of evolution and without radicular symptoms radiated to the head. Neck pain intensity with a visual analogue scale (VAS), neck disability index (NDI), CPM, and cervical rang of motion will be measured pre and port intervention.

Inclusion Criteria:

• aged 18-65 years.
• neck pain perceived in the posterior region of the cervical spine, from the superior nuchal line to the first thoracic spinous process with more than 12 weeks of evolution and without radicular symptoms radiated to the head, trunk, and/or the upper limbs.
• the ability to understand, write, and speak Spanish fluently

Exclusion Criteria:

• development of systemic or degenerative diseases;
• symptoms of depression according to Beck's questionnaire.
• pain in any area between the lower back and the head in the last 9 months.
• neck pain associated with whiplash injuries.
• medical red flag history (i.e., tumour, fracture, metabolic diseases, rheumatoid arthritis, osteoporosis). - neck pain with cervical radiculopathy.
• neck pain associated with externalized cervical disc herniation.
• fibromyalgia syndrome.
• previous neck surgery.
• neck pain accompanied by vertigo caused by vertebrobasilar insufficiency or accompanied by non-cervicogenic headaches due to a traumatic event in the past 12 months.
• and history of neck or face pain in the last 6 months.