In this research study we want to learn more about if transcutaneous electrical nerve stimulation (TENS), a safe electrical stimulation tool, can relieve Fibromyalgia pain. A total of 60 subjects with Fibromyalgia will be enrolled in this study at Massachusetts General Hospital, Charlestown Navy Yard campus.

Inclusion Criteria:

• Meet the American College of Rheumatology (ACR) 1990 classification criteria and the ACR 2010 diagnostic criteria for fibromyalgia as determined by clinicians.
• Willingness to complete a 4-week, twice-a-day treatments.
• At least a 10th grade English-reading level; English can be a second language provided that the patients understand all questions used in the assessment measures.

Exclusion Criteria:

• Diagnosed with medical conditions that are known to contribute to fibromyalgia symptomatology, such as thyroid disease, inflammatory arthritis, systemic lupus erythematosus, rheumatoid arthritis, myositis, vasculitis, or Sjogren's syndrome.
• History of cardiac, respiratory, or nervous system disease that, in the investigator's judgment, precludes participation in the study because of a heightened potential for adverse outcome. For example: asthma or claustrophobia.
• Personal history of medical or psychiatric illness as determined by investigator.
• Pregnant or lactating.
• Less than a 10th grade English-reading level; English can be a second language provided that the patients understand all questions used in the assessment measures.