Problems with the jaw joints, muscles, or nerves can all cause pain. Long-lasting jaw pain may indicate a temporomandibular joint disorder, or TMD. TMD pain can affect either or both sides of the face. The temporomandibular joint is made up of bones, muscles, ligaments, and discs. It's a complex system that lets us talk, chew, and even yawn. If any part of the system isn't working right, you can feel pain.