A visual analog pain scale and scalar responses to 13 pain/symptom indicator Symptom Checklist-90-Revised (SCL-90-R) questions were used to assess symptom prevalence and pain severity in 43 chronic orofacial muscle pain patients and 40 control subjects. The orofacial muscle pain group reported pain in an axial skeletal distribution; neurocognitive, gastrogenitourinary, and musculoskeletal symptoms; infectious events at or preceding onset; similar symptoms in sexual partners; and low prevalence of trauma. Sudden onset was reported by 30.2% of pain patients. Strong associations were found between chronic orofacial muscle pain and (1) onset-related infectiouslike events (67.4%); (2) a higher prevalence of history of respiratory and gastrogenitourinary infectious events; and (3) high prevalences of similar pain symptoms in long-term sexual partners. The sCL-90-R somatization scores (> 62) had a higher prevalence in the chronic pain group. No prevalence differences or associations with pain/symptom indicators were found for depression or anxiety dimension scores. These data suggest that patients with recurrent systemic infectious events have a higher prevalence of reporting of chronic orofacial muscle pain compared with control subjects, and these infectious events are associated with the onset of chronic orofacial muscle pain in 67% of patient