Deep dry needling with or without median nerve tension in patients with neck pain

The intervention consists of applying median nerve tension and deep dry needling in the upper trapezius of 14 patients with non-specific neck pain. A physiotherapist will administer the intervention at a single 30 min session, performing the needling plus median nerve tension in the most painful location of the upper trapezius as well as gathering data about every other variables measured. Another physiotherapist will be present for any help requiered. The main variables measured are: - Activation of the Autonomic Nervous System by measuring skin conductance and heart rate variability: both variables will be monitored by biofeedback NeXus 10 MK-II 5 minutes pre-intervention, during the intervention and 10 minutes post-intervention. - Amount of pain using the Verbal Rating Scale: participants must answer how much pain from zero (no pain) to ten (maximum pain) do they feel both before and after the procedure. - Pressure pain threshold: minimum pressure (mean of three measurements) at which participants experience pain in C5-C6 facet joint will be registered using an analog algometer Wagner Force Dial™ both pre and post-intervention. - 'Pain Catastrophizing Scale' and 'Neck Disability Index': both questionnaires must be filled in before the procedure begins.