I had something similar when I was taking molybdenum for several years. Apparently I had gotten to point to where I was overdosed and didn't need it any more. I discontinued and the pains cleared up in a few days.
There was one other supplement which caused a similar thing around the same time, which, of course, I can't remember what it was. I discontinued that and things cleared up in a few days.
One caused rib pains and the other caused a pain in my thigh, both on my left side.
I think I figured out the cause by self muscle testing.