The MRI is a good plan. The shot helps alot of people, but not all,from what I hear. I did it once, only lasted about 3 weeks. Physical Therapy may help in your case.
As you can see, I'm up, it's 3AM in Alaska....thinking about going back for another shot...I need to sleep, can't take it any more....miserable......I wish I had been your age when it started. 43 here and figure I'll suffer the rest of my life