Sure it could be from something else than BCG, like the beginning of arthritis...but yes, I hate to say it but it could be from BCG. I know a few women who were left with lasting symptoms. If it's from BCG it could go away, if it's something else it probably won't.
Have you spoken with your doctor about it?
Some time ago I had the same side effects from treatments for breast cancer (Tamoxifen and Zoladex), pain in the hips and back, I couldn't walk very well for about 6 months but did not get a lot of sympathy from the doctors. Pain killers didn't help. We got a new bed that rises at the head and feet (witha buttom) and it helped a whole lot. The symptoms went away. Even though xrays and bone scans showed the beginning of osteoporosis (at 43?).
All the best,
Wendy