Tetanus. If you have an open wound that occurred when outside or has been in contact with soil or there is a puncture wound these are higher risk for tetanus.Tetanus (lockjaw) usually starts with mild spasm of the jaw as well as the chest, neck, back and abdomen. Get tetanus shot if it has been > 10 years since your last tetanus shot or your don't remember when it was.
See your doctor. This is a problem that requires a face-to-face meeting with your doctor. In that meeting, your doctor will listen to you, perform a throrough examination and possibly order labs or other tests. Based on this information, he/she will be able to tell you what's wrong and what to do about it.