What Causes Bruising Around Stomach Towards The Belly Button?

My husband has a large area of bruising down his left side. It extends from just under his arm to the top of his hip. It has moved around his stomach towards his belly button and wraps around his back as well. He recently had a very bad bronchial cough that lasted for about 3 weeks. He was in to emerg twice, the second time because he had pain in his chest just below the breast bone. It was determined that is was muscular because of the violent coughing. I don't know if this could have anything to do with it. The only thing he has done that he can think of is he leaned into a grain bin on that side. He's done this many times before without this kind of bruise. Do you have any idea what it could be. He takes baby aspirin as a blood thinner, statin drug for colesterol, Crestor for blood pressure and verapamil for irregular heart rate.