The inability to open your mouth fully is often accompanied by pain when you get to the widest you’re able to open.  This condition occurs when the disc of the TMJ slides out of position and then becomes an obstacle to normal joint function.  Use warm compress for 20 minutes at a time, try to allow your muscles to relax, and wiggle in whatever way you’re able to move.  Doing this should help to unlock this position.  If you are unable to reach success on your own, please contact our office and we’d be happy to help you resolve this issue and offer treatment options to stabilize the joint to prevent future complications.