Thanks for your question on Health Care Magic. I can understand your son s situation and problem. Your son is having blunt chest trauma due to football hitting. Usually this does not cause any major internal damage. But since he is having reddish stool, we should rule out internal damage like stomach injury or lung injury. So better to get done chest x ray to rule out lung injury. If chest x ray is normal than no need to worry for lung injury. Get done stool microscopic examination. If it is positive for red blood cells than he needs upper GI scopy for the diagnosis of stomach injury. If stool examination is normal than no need to worry much. Hope I have solved your query. Wishing good health to your son. Thanks.