Breast tenderness and shoulder pain at the same time may be due to physiological reasons, such as excessive fatigue. It may also be due to pathologic reasons, such as breast hyperplasia, bone fracture or cervical spondylosis. 1. Physiological causes: overwork may cause this condition, for example, over-exercise leads to shoulder and chest muscle fatigue, and then the patient feels pain in the above areas. 2. Pathological causes: These include breast hyperplasia, bone fracture, or cervical spondylosis. (1) Mammary hyperplasia: Mammary hyperplasia can occur around the ducts, manifesting different degrees of papillary hyperplasia with cystic dilatation of the milk ducts. Pain is the basic manifestation of breast hyperplasia, and sometimes the pain may be predominantly in the area of the lump, radiating to the back of the shoulder and armpit. (2) Fracture: there may be trauma to the thorax, such as direct impact on the thorax in a car accident, which may easily cause fractures of the scapula, ribs, clavicle, etc., which in turn may cause pain in the above areas. (3) Cervical spondylosis: Due to long-term strain on the cervical spine and osteophytes, the nerve roots or cervical spinal cord are compressed and the sympathetic nerves are stimulated, which leads to cervical spondylosis. The onset of cervical spondylosis is characterized by radiating pain from the neck, shoulder and upper arm. If you feel unwell, you should go to the hospital in time to find out the cause of the disease and receive treatment according to the doctor’s instructions, so as not to delay the condition.