Had a friend who had a injured his achilles playing football, the trainer looked at it, they ran some tests and xrayed it, couldn't see a problem. He struggled with it for a while, then he went to the ortho doc, had an MRI done and there was a partial tear on the interior. He made it worse by trying to work through the pain and it would have been so much better had he gotten off of it right away and had it fixed immediately. Get it looked at right away.