In adults, this can be related to overload and inflammation of the plantar fascia (plantar fasciitis), the fat pad surrounding the heel, and/or a heel spur. In children aged 8-14, heel pain is likely to be a common overuse injury called Sever’s Disease, where the growth plate at the heel becomes inflamed.
A plantar fascial tear and a growth plate fracture can go undiagnosed, so make sure you seek professional advice promptly, particularly when there is an inability to bear weight on the foot.