What Causes Pain In The Jaw?

About three weeks ago I had a cavity refilled. Since then I have been back in the office for 2 bite adjustments. Obviously, my mouth had some irritation from the bite being off. Within this time I also found out I was pregnant. Since my last bite adjustment, about a day later, I have had severe pain in my jaw. It wraps around the top jaw line around to the bottom. Taking tylenol and applying an icepack do make the pain go away, until the tylenol has worn off. I am a known tooth grinder, but can this pain be all muscle related from the grinding? I have switched to soft foods to help eliminate more chewing than neccessary. The pain is the worst at night. And I definately wake up right at the 4 hour mark when the tylenol has worn off. My dentist is not in for another day, which will make it 5 days with the pain. I am worried that there might be something more than just muscle issues from grinding. And being pregnant makes the worry even more. Any help would be appreciated.