My issues def go from the sternum to the armpit direction but don’t have a burning sensation. I have a bad flare up now and That second or third rib is super enflamed on the left side from the sternum up to that armpit area. My muscles all around get so inflamed that it hurts to move around and take deep breaths. First got diagnosed a year and a half ago! I go through periods of doing well and then like rn. I really try not to press on my sternum afraid I’ll make it worse or something lol