From the way you are describing it, seems to be of "musculoskeletal' origin ie either skin, cartilage
, muscle or bone in that area is the likely cause.
However, given the fact that you have diabetes
, it is important to rule out a heart condition. So definitely I would recommend a cardiac work up to ensure this is not acutely worrisome.
Once a heart problem is ruled out, then it would be worthwhile doing an Xray to see if there is a fracture
of the rib in that spot.Actos
has been reported to raise the risk of fractures of the forearm bones in women after menopause