I have pain in the right upper back and sometimes a stabbing pain under the right breast. The pain is worst by laying down on right side or sitting and putting pressure on it. It,s  been going on for a few years on and off. Sometimes the way I move the pain gets worst.
This sounds musculoskeletal in nature. I would use topical ice, but if it has been going on for years, then you should seek a referral for physical therapy as well as massage therapy. This could also be accompanied by local muscle trigger point injections. And if those don't work, then a trial of acupuncture would be beneficial. And once you do see your doctor, a chest x-ray would be warranted just to rule out any rib or lung abnormalities.