There are many reasons for a hard lump inside the chest, and the specific analysis is as follows: 1. Sternal fracture protruding from the skin surface. The fracture needs to be reset and fixed to prevent misalignment healing. 2, skin disease. For example, sebaceous cysts, subcutaneous fibroids or lipomas can be examined by ultrasound. Surgical removal is required. 3. Skin allergy. For example, poor quality clothes, skin allergies and long papules, need to replace good quality clothes, anti-allergy treatment. 4, subcutaneous lymph node enlargement. Simple swollen lymph nodes can be felt as smooth hard lumps with a certain degree of activity, and when inflammation is obvious, it will be accompanied by pressure pain, and can be infused to reduce inflammation. If the lymph nodes are large, they can be removed surgically. If the lymph node metastasis is caused by breast cancer or lung cancer, anti-cancer treatment is needed, and surgery plus chemotherapy can be performed in the early stage, while chemotherapy needs to be adhered to in the late stage.