A bony prominence on the back of your heel is called a ‘calcaneal bump’. These are most commonly associated with a high-arched foot. The back of the heel pushes and rubs against the back heel counter of the shoe. Both the tendon and soft tissues can become inflamed and painful when this occurs.
Causes: In a high-arched foot, the heel bone (calcaneus) can have an altered alignment, which causes an enlargement of the bone in the back of the heel. Often, the body will create a fluid-filled sac (bursa) in order to protect the tendon and other soft tissues. When wearing shoes or boots, this bursa gets pushed up against the heel counter, and becomes very painful.