I could certainly be arthritis .... I'm sure this could and probably was diagnosed in the report of your Bone Scan. It could also be a delayed result of the Chemotherapy. I wonder if by any chance you might be on Tamoxifen or another similar drug following your Chemo. If so, this could certainly be the cause. Regards ....
What kind of chemo did you receive? I am thinking it might be a combination of the chemo and some OA (Osteoarthritis).
I've got the same bone and joint pains and mine started during chemo two years ago. Tamoxifen kept the pain chain going :)
I was tested for arthritis and am happy to say that is at least ONE thing I don't have.