Hi. Thanks for your query. Noted the history about your fall from a horse last Sunday, have 5 bowel movements since then, much like diarrhea, hit lower left back area with bruising over kidney area, there is stomach pain, wants to know to tie up the symptoms and decide whether to see a Doctor. Since there is a history of fall and injury over left lower back, it is imperative to have clinical evaluation, examination and investigations. I would advise you the following: CT scan of the abdomen including the study of the retro-peritoneal area as retro-peritoneal hematoma can cause irritation of the intestines and colon to cause the loose stools like diarrhea. The treatment is usually conservative as the surgery may not be needed. Needs symptomatic and supportive treatment in the form of intravenous fluids and electrolytes. This may then settle with time.