Your situation is not unique. This is usally caused by contractions of muscles that close the jaw. It seems likely that heavy clenching, as is possible under the conditions you described, can create severe muscle tension and pain.

Usually there is an underlying TMJ problem related to your face and head muscles which then cause headaches and pressure on the inner ears resulting in ringing sounds, nausea, and equilibrium disturbances.

1. See your family doctor for a comlete examination in order to evaluate for any underlying issues.
2. See your dentist and tell him/her this problem. Your dentist or a TMJ specialist have a number of ways to help you after a diagnosis is made.