Achilles tendon pain can be due to Achilles tendonitis (inflammation) or tendonosis (degeneration). These conditions can result from increased strain over a long period of time, returning to activities after an extended period of inactivity or a sudden increase in speed or distance of activity. Tightness of the calf muscles, excessive rear-foot pronation ('ankles rolling in') can increase the likelyhood of injury to the Achilles tendon.
People suffering from Achilles tendon pain can experience it during activity or after. Pain or stiffness may be present in the morning also. The pain is usually felt behind the heel and sometimes along the tendon up the leg.
Treatment can vary depending on the cause of the pain but can generally include: Icing, rest, correction of any over-pronation, footwear advice, NSAIDs.