Inclusion Criteria:  Age over 18 years; Moderate to severe pain score according to the Numerical Pain Scale (4-10); Persistent pain and refractory to clinical treatment for at least 3 months; Appropriate pharmacological treatment for pain for at least 1 month before the start of the study; Not presenting contraindications for Non-Invasive Brain Stimulation; Absence of concomitant diseases of the Central Nervous Sistem or Peripheral Nervous Sistem.  Exclusion Criteria:  Failure to sign the informed consent form; Missing two consecutive or three alternate sessions during treatment; Developing a disabling condition that prevents further participation in the study