title: Pain: usually just a symptom, but it can be a disease state.
mesh_terms: D003937:Diagnosis, Differential; D005156:Facial Neuralgia / Q000175:diagnosis; D006801:Humans; D010146:Pain / Q000209:etiology*; D011602:Psychophysiologic Disorders / Q000175:diagnosis; D014098:Toothache / Q000175:diagnosis