Is the pain right in the middle like spinal / disc pain, or off to one side right above a butt cheek? If it's off to the side and lower, you might ought to see a good massage therapist. I had what I thought was back trouble for years, and some of the worst pain would randomly pop up when I was straightening up from tieing my shoes. Turned out to be a severely pulled muscle that would never heal completely. I was going to physical therapy, and a new therapist asked if she could try something, since she was also a licensed massage therapist. She had me lay on my stomach and went to work on it, and in 5 minutes I was good as new! Not gonna lie....it hurt like a S.O.B. when she first got started! After she got the knot worked out of the muscle, the pain eased up and just went away.