What Causes Constant Pain Under The Mid Area Of Chin?

I have constant severe pain under my mid area of chin. I've had TMJ for several years but no pain from it for over 2 years. Until the last 3 months I've had this chin pain. I haven't had any dental work done. I was wondering if I could have caused nerve damage because I'm at the computer for work around 10 hours a day and I tend to lean on that part of the chin. I've been taking Ibuprofen and Tylenol just to ease the pain. I've seen my Dr. and he said it's "probally just TMJ" and left it at that. Perscribed me 800 mg Ibuprofen. Any ideas. Thanks, Ginger