Breast pain causes back pain for many reasons, the specific analysis is as follows: 1, psychological factors. For example, mental stress or serious mental illness, resulting in abnormal body sensations, manifested as breast pain and back pain. 2, breast enlargement. The lumps of mammary gland hyperplasia patients will have swelling and stabbing pain under the influence of increased estrogen, and those with severe pain will have involvement pain, leading to back pain. 3. Breast cancer. The cancer cells of cancer patients invade the nerves leading to breast pain, and if metastasis occurs in the later stages of breast cancer, it may lead to back pain, which requires high vigilance. 4. Breast disease combined with cervical spondylosis, which will manifest as shoulder and neck pain and arm numbness. 5. Breast disease combined with frozen shoulder. Breast disease combined with intercostal neuritis.