Haglund’s deformity is an enlarged portion of bone found posterior to the heel bone and is a painful issue commonly faced by runners. It can be difficult to address. The prominent portion of the heel bone rubs against shoes, leading to pain and blisters. This bursitis may be quite inflamed. https://runningone.net/how-to-deal-with-a-bony-bump-at-the-back-of-the-heel/