Plantar fasciitis is the most common cause of heel pain in adults. Severs disease (calcaneal apophysitis) is the most common cause of heel pain in children.
Severs disease is an overuse injury of the growth area at the back of the heel bone in children from around age 10 to the mid-teenage years. This growth plate merges with the rest of the heel bone at those mid-teenage years to the condition does not happen after that age and adults do not get Severs disease. It is most common in active children and the classic symptom is pain on the sides of the heel bone when squeezed by the fingers (the classic sign of plantar fasciitis is that first step pain in the morning does not happen in Sever’s disease).
The treatment of Sever’s disease is usually to reduce activity levels to what the tolerable level is. A different activity could be substituted. A cushioned heel pad is also often used. That generally will take care of most cases. The more severe cases may need to go into a moon boot for up to a month or so to further restrict activity of the child.