Heel pain is not usually caused by a single injury, such as twist or fall, but from repetitive stress and pounding of the heel.

Heel bursitis: pain may be felt deep inside the heel or at the back of the heel)

Heel bumps: these are common in teenagers. The heel bone is not yet fully mature, and it rubs excessively. 

Tarsal tunnel syndrome: A large nerve in the back of the foot becomes pinched or entrapped (compressed).

Chronic inflammation of the heel pad: This is caused either by the heel pad becoming too thin, or through heavy footsteps.