If the pain is in the upper back of the heel, it could be Achilles tendonitis, a condition that involves the inflammation of the Achilles tendon. The Achilles Tendon is the longest tendon in the body, and its main function is to connect the calf muscles to the heel bone behind the ankle joint. When the calf muscles contract, they pull on the Achilles Tendon, causing your foot to point down and helping you rise on your toes. Achilles pain occurs just above the back of the heel. Sufferers of this condition also experience tightness in the calf muscles. The Achilles Tendon may be noticeably thickened and tender to the touch in this area. Pain is present when walking, especially when pushing off on the toes.
One of the most common causes for Achilles Tendonitis is the flattening of the arches also known as excessive pronation. When the feet roll inwards and the lower leg is forced to rotate internally, it creates a tearing force on the calf muscles. Since the calf muscles are connected to the Achilles tendon, it turns out to be the 'weakest link' in the chain. The Achilles tendon ends up being overstretched, resulting in irritation and inflammation.
Over-pronation can be corrected by using orthotic arch supports. For more information, please refer to links below.