Hi Lot of blood in stool and anal/rectal pain may mean an anal fissure, hemorrhoid or just chronic constipation.Less common causes of bloody stool in your case may include cancers and inflammatory bowel diseases.You may need to have your rectum examined by a Doctor to ascertain the cause.In the meantime, you may take pain medications like ibuprofen, drink enough water and take enough fruits like soft pawpaw to make your stool as soft as possible.Avoid dry and baked foods and avoid fruit like bananas which may instead constipate you.If the bleeding persist, you see a Proctologist for a rectal examination and a rectoscopic/coloscopic exam. Hope my answer will help you Best regards