One of the things that can cause this type of pain is if the filling is a little high - they pull that little strip of paper to make sure that the teeth are not rubbing, but sometimes you hold your jaw a bit differently and they don't catch that a bit of the filling is high. The dentist can usually fix that really quickly. My dentist will have me come in on an emergency basis when this happens and check for it - or for any other possible cause, of course - if it's the filling, it just need to be ground down a little bit, and then usually you are good to go. Will take another day or so for it all to subside.