Leg pain in a 14-year-old boy is not necessarily calcium deficiency, it is recommended to seek further clarification of the etiology, which may be related to growing pains, vitamin D deficiency, osteosarcoma and other etiological factors. 1. Growing pains: they often appear during puberty, mainly manifested as pain in both lower limbs, which is more obvious at night. Usually, there is no obvious abnormality in the examination, and normal activities can be carried out without redness or swelling in both lower limbs and joints. 2. Vitamin D deficiency: Vitamin D, bone density and other tests can be further improved, if there is a decrease in vitamin D, bone density reduction, etc., it is necessary to consider the cause of the disease. 3. Osteosarcoma: occurring in adolescents, can be manifested as pain in the lower limbs, pain intensified after activities, and masses can be touched in the late stage, which can be further improved by X-ray, CT and other examinations. In addition, 14-year-old boy leg pain may also be trauma and other causes, it is recommended to consult a doctor to clarify the diagnosis, as soon as possible for targeted treatment, so as not to miss the opportunity for treatment.