If your child is complaining of heel pain, in the absence of any significant injury e.g. a hard landing with massive ground shock, it’s possible that they have Calcaneal Apophysitis – otherwise known as Severs’ Disease.

The basic premise of Calcaneal Apophysitis is that it is an overuse type injury, exacerbated by the rapid growth of the bones in the lower leg, while the muscles struggle to keep up. The muscles are shorter, therefore more highly tensioned, and the growth plate in the heel is being constantly tensioned, creating irritation, pain and a lack of enjoyment of activity.
 
This document supports diagnosis and provides exercises, stretches and more.