45 yo male, 5'10",170lbs., and healthy. Fell on my back 2 weeks ago, at which time the left lateral side of my chest hurt, midway up rib cage. Two days later I felt more pain in my back than my chest. Now both chest and back are mildly uncomfortable, with mild dull pain that feels like it's located deep, and becomes painful with exertion. It has not been too painful to prevent me from traveling or shoveling the driveway. Does this sound muscular, with rest being all that's needed? Or should I get checked out?