Inclusion Criteria:  Formal diagnosis of fibromyalgia syndrome (FMS). No change in the last 4 weeks on their standard treatment. They must have pain for more than 6 months (at least 4 on the VAS scale). Score on the fibromyalgia impact questionnaire (FIQ) greater than 39.  Exclusion Criteria:  Presence of concomitant autoimmune or hematologic diseases. Neuropsychiatric disorders. Pacemakers or neurostimulators implants. Substance abuse or other pathologies that can explain chronic pain. Pregnant or lactating women. Those who are receiving any other type of physiotherapy treatment.