<s>[INST] Hi, I was running a race last Sunday and fell and landed on my heel quite hard. In the shower tonight I have noticed a small lump inside my butt cheek near my anus. It is quite painful to sit in certain positions. Could this be anything to worry about? [/INST] It could be a thrombosed pile or an abscess. Unlikely to be due to the injury. If it is due to the injury it could be a blood collection or hematoma. I suggest you get examined by a Surgeon who would be able to tell you what it is. It is quite difficult to say with certainty what it is. Examination will with great purity reveal what it is and then treatment can be initiated accordingly. Take care, Chat Doctor.  </s>