The right leg pain of an eleven-year-old girl, which is sometimes swollen and painful, may be related to overactivity, calcium deficiency, inflammation and other factors. 1. Excessive activity: If a girl’s activity level has increased recently, such as running or swimming, it may lead to joint muscle strain, which may lead to leg pain. 2. Calcium deficiency: Calcium deficiency can also lead to the above situation in girls, and some girls may also experience leg cramps. 3. Inflammation: girls with inflammatory diseases of the bone and joint, such as rheumatism, may have the above symptoms, accompanied by fever. Eleven-year-old girl’s right leg pain, sometimes swelling and pain may have other causes, it is recommended to timely go to the hospital for relevant examinations, clear causes and then actively treat the symptoms.