I've been dealing with hip and back pain for about 18 months now. At times it is so bad that even wearing a lightweight pistol OWB is too much, due to pressure on the waist line. The only options I've found to work when the pain is really bad is pocket carry or shoulder rig. Neither is a good solution in a grappling situation, but better to have a gun than bad language.
I tried a bunch of different handguns in the pocket, and found that the best solution was the LCR .38. Tried several semis, but the weight was an issue (back to having to wear a pretty tight belt to keep my shorts from falling off).
Shoulder rig obviously allows a much more substantial handgun to be carried.