The symptoms of breast cancer spreading to the lung are cough, hemoptysis and chest pain, which are more common manifestations, but some of them are not more obvious, as follows: 1. If the lump is small and the metastatic lesion is early, the symptoms are not obvious and need to be found through usual follow-up review; 2. If the lung breast cancer is metastatic to the lung, the metastatic lesion in the lung is concentrated in the periphery, and the symptoms of chest pain may appear; 3. If it is concentrated in the main bronchial tubes, coughing or hemoptysis may occur; 4. If the metastatic lesions become larger and larger, breathing difficulties may occur, so regular follow-up review is necessary. If early lesions are identified, surgical treatment can be performed.