I'm a dental nurse in my spare time(?!) and it definitely sounds to me like you've dislocated the disc in your TMJ. An oral surgeon should be able to manipulate it back in place without surgery (try not to have surgery)... also a physiotherapist with a specialty in TMJ could help you by giving you exercises to do regularly. Maybe you could have a splint made up by a dental technician to help you keep your jaw relaxed at night. (Physio and Tech AFTER the oral surgeon)

Good luck!!