This is the most common complaint. It is called Plantar Fascitis.

Most cases of heel pain are characterized by inflammation. First, the fascia begins to pull on the bone and the tissues become irritated, then inflamed. Inflammation of the fascia is called fasciitis.With the continuous inflammation & stretch, over time the bone might respond by forming a protuberance called the HEEL SPUR. This can grow where the muscles of the foot attach to bone. While some heel spurs are painless, others that are determined to be the cause of chronic heel pain may require medical treatment or surgical removal.

Symptoms:
Classically, it presents as Heel pain in the mornings on arising or after starting to walk after an extended period of sitting - becoming less painful as you begin to walk and the pain dissipates.