Temporomandibular joint disorder

Temporomandibular joint disorder (TMJ/TMD) can cause jaw pain and pain in the muscles that control your jaw. A combination of factors can cause this disorder such as genetics, arthritis or jaw injury.

(TMJ/TMD) is an additional symptom of ME/CFS.

ME/CFS and Fibromyalgia
TMJ/TMD "causes jaw pain, and it's more common in people with Fibromyalgia (FMS) and Chronic Fatigue Syndrome (CFS or ME/CFS) than it is in the general population."