I got squeezed in to see my onc late yesterday afternoon and it turns out the xray was good -- no evidence of anything new. As he said, "sometimes pain is just pain." But I did the right thing in reporting it and getting it checked out.
Maybe it was the change of seasons? Arthritis? Overuse? Sleeping on that side and having the rod in my hip rub against tissue? Either way, I haven't had that pain since the end of last week.