I'm not an M.D., but you definitly need a 2nd opinion. You didn't mention your location so you might do what I did a year ago when I was diagnosed with my brain tumor. I read about the best hospitals in the U.S.A. and went to the one nearest my home, just to talk to a specialist who filled me in on all the details.
The July 18,2005 edition of "U.S. News & World Report" just came out and it ranks the nations best medical centers in order for 17 different specialties. In your case you may need to look at the Orthopedic section, Rheumatology, or Neurology sections to see if a top notch hospital is near you. Your problem could be related to any of these. Then I would call and see if you could get an exam appointment so the doc could examine you and your MRI's. Make sure you get a copy of your MRI's so a 2nd doctor can review them with you. I hope this helps, it's a start anyway. Will workman's comp. cover a 2nd opinion?
Might be worth paying for the 2nd opinion if the pain is that severe. I wish you well.