Why is my jaw causing me a lot of pain?

it sounds like TMD, a disorder of your Temporomandibular Joint. This occurs when the cartilidge in the joint either shifts out of place, wears itself down, or even folds over on itself. Over time it can get worse and cause wearing as bone rubs against bone, causing pain and the jaw can lock up. You can see an orthopedic surgeon for treatment, and anti inflammatory drugs can help the pain while you and your doctor decide whats best. I have this disorder too, so if u have any more questions at ALL u can email me. Hope u feel better hun :)