The common causes of heel pain in 9-year-old boys include physiologic factors, trauma, plantar fasciitis, Achilles tendonitis, and so on. 1. Physiological factors: for example, standing for a long time, walking too much, etc., resulting in muscle fatigue around the heel, which in turn causes heel pain. Usually, it can be relieved with proper rest. 2. Trauma: If the heel is impacted by external forces, causing localized injuries, it is easy to produce localized pain symptoms, which may also affect walking. 3. Plantar fasciitis: caused by repeated pulling injury of the plantar fascia, usually manifested as pain in the heel and its surrounding area, and the pain is most obvious in the morning when walking after getting up. 4. Achilles tendonitis: related to the Achilles tendon repeated strenuous stretching, usually causes severe heel pain, but also manifested as redness and swelling of the Achilles tendon area, mobility difficulties. All in all, if a 9-year-old boy suffers from heel pain for a long time, it is recommended to go to the hospital in time to avoid aggravation of the condition.