The main causes of breast pain in 9-year-old girls include the following: 1. Symptoms caused by precocious puberty in children, children with breast pain at the age of 9 weeks, coupled with the onset of menstruation and significantly earlier bone age, should be considered to be caused by precocious puberty, children need to apply drugs to de-stress the liver to deal with it, such as the application of prozac; 2. The pain is caused by trauma to the breast area, after the trauma to the breast area will also cause local pain, you can carefully ask the history of trauma; 3.