Myofascial pain syndrome (MPS) is initial to other pathologies such as neck pain or tension headaches; the symptoms that are located on the area of myofascial trigger points (MTrPs) of specific references in different muscles. MTrPs are palpable, tense bands found in stiff muscle that cause pain and swelling. They affect the disruptive soft tissues, resulting in deterioration of the muscle and fascia; effects that can be transferred further, through the myofascial chain to distant tissues, inducing the referred pain that is the main feature of MPS. MTrPs are treated with stretching, massage, analgesics, acupuncture, dry needling, electrical stimulation, and ultrasound. Percutaneous microelectrolysis (MEP®) is a new technique that uses galvanic current of low intensity and high density. Based on the previous reviews, the investigators consider that the use of MEP in individuals who have MTrPs in the trapezius is more effective than acupuncture treatment. Objectives: To assess the effect of MEP as a technique for treating pain in MTrPs of the trapezius muscle compared to without current emission, analyzing function, pain and strength in MTrPs before and after both treatments.

Myofascial pain syndrome (MPS) is initial to other pathologies such as neck pain or tension headaches; the symptoms that are located on the area of myofascial trigger points (MTrPs) of specific references in different muscles. MTrPs are palpable, tense bands found in stiff muscle that cause pain and swelling. They affect the disruptive soft tissues, resulting in deterioration of the muscle and fascia; effects that can be transferred further, through the myofascial chain to distant tissues, inducing the referred pain that is the main feature of MPS. MTrPs are treated with stretching, massage, analgesics, acupuncture, dry needling, electrical stimulation, and ultrasound. Percutaneous microelectrolysis (MEP®) is a new technique that uses galvanic current of low intensity and high density. Based on the previous reviews, the investigators consider that the use of MEP in individuals who have MTrPs in the trapezius is more effective than acupuncture treatment. Objectives: To assess the effect of MEP as a technique for treating pain in MTrPs of the trapezius muscle compared to without current emission, analyzing function, pain and strength in MTrPs before and after both treatments.

Materials and methods: Randomized controlled clinical research. The study population consists of patients of both sexes between 20 and 60 years of age, with medical referral for neck pain who do not currently receive physiotherapeutic treatment, pain of at least 1 month of evolution, presenting on both sides of the trapezius MTrPs muscle and having signed the informed consent. They will be randomly distributed into: group treated with acupuncture (control) and group treated with MEP. Both will take place over 3 weeks, with one session per week. The evaluation is carried out through the visual analogue scale (VAS), measurement of force with a dynamometer and mobility with a goniometer. The score will be recorded on a validated neck pain questionnaire (NPQ). The Chi-Square test (test) will be implemented for the analysis of categorical data and the "t" test for paired data for quantitative data, based on a significance level of p˂0.05 in all cases.

Inclusion Criteria:

• with medical referral for pain of at least 1 month of evolution
• presenting on both sides of the trapezius MTrPs muscle

Exclusion Criteria:

• neck pain who do currently receive physiotherapeutic treatment of at least 1 month of evolution

Both groups do not know if the treatment has emission or not while the sessions are carried out.