Hello! I have been through your question. According your symptoms I think these are hemorrhoids signs. Usually this could happen when the veins around your anus tend to stretch under pressure and may bulge or swell. Swollen veins (hemorrhoids) can develop from increased pressure in the lower rectum due to straining during bowel movements, consistent heavy lifting( the most probably cause in your situation) , sitting for long periods of time on the toilet, chronic diarrhea, constipation,obesity,anal intercourse, low-fiber diet. Signs and symptoms of hemorrhoids may include painless bleeding during bowel movements, itching or irritation in your anal region,pain or discomfort, swelling around your anus or a lump near your anus, which may be sensitive or painful. Your doctor can do a physical examination and perform other tests to confirm hemorrhoids and rule out more-serious conditions or diseases. I hope my answer help you. I wish a quick recovery.