Lumps on the chest of boys may be caused by lipoma, breast hyperplasia, nipple inflammation and other reasons. 1. Lipoma: Lipoma can grow in any part of the body with fatty tissue, chest is no exception, so boys chest more lumps may be lipoma, lumps are generally small, soft and flexible. 2. Breast hyperplasia: the main symptom of breast hyperplasia is breast lumps, in addition, there may also be breast pain, nipple discharge and so on. 3. Nipple Inflammation: Some men may have nipple inflammation due to trauma or mechanical friction, etc. The nipple is subjected to long-term friction or pressure and other thorns resulting in skin breakage at the nipple, which increases the sensitivity of nipple pain. In addition, breast tumors, pleural tuberculosis and other conditions can also cause lumps on the chest of the boys, it is recommended that patients seek medical attention in a timely manner to clarify the specific causes of the disease under the guidance of the doctor for appropriate treatment.