I was dx w/ the flu 4 weeks ago.as resolving, i got a sharp/stabbing pain under left breast/rib area (last week).it is very painful when pressed, sneezing, coughing or breathing in.urgent care did xray-dx reactive airways,but does that explain pain??

You coughed a lot when you had the flu which can crack a rib or the costochondral joint which was not detected by a plain chest X-ray. Your pain is consistent with rib cage pain which makes you stop the sneeze due to anticipated pain. Just hold that site when you cough, sneeze or take a deep breath. Usually the pain will subside in a week or two. Take ibuprofen, as needed, if no contraindication.