How do you know if you're getting lockjaw? do you just wake up with it?

Limited movement: The condition is usually caused by muscle spasm usually due to clinching or grinding of you teeth. It can also be caused by jaw joint derangement or wear and tear. Moist heat compress and jaw stretching exercises will help. Soft diet for a few days till the symptom goes away. If this is a frequent event, appointment with your dentist is needed. He/she may refer you to a specialist.