<s>[INST] My husband was doing a push-up at his correction class and came down hard on his knuckle to his chest. His chest has been hurting him badly for a few weeks now to breath deeply, cough, or sneeZe and now has a bump where he hit it... What could this be? [/INST] Hi and welcome to HCM, This is due to injury only.  there may be some stasis of blood.   Take x-ray of chest AP view to rule out any fracture of rib.  Apply Thrombophobe locally.  Wish you speedy recovery,  Thanks </s>