as you already had breast cancer
on the same side with the removal of the rib, which may be suggestive of involvement of the bone(rib) on same side by the cacner. The pain due to infiltration by malignancy is a continous type with local tenderness.i need to know the histopathology of your operated breast speciman for bone involvement. Malignant pains should be treated according to WHO ladder based drugs, starts with NSAIDS like voveran
etc. you can also consult palliative care
specialist for the same.