Pain caused by the breast cancer itself usually comes from one of two sources:
The tumor in the breast: Pain is not a common symptom of early breast cancer, but a tumor can cause pain as it pushes into nearby healthy tissue. For women with inflammatory breast cancer, pain or tenderness often is one of the first symptoms. This rare type of cancer tends to grow quickly and causes reddening and dimpling of the skin over the breast. A rare form of breast cancer called Paget's disease of the nipple can cause pain and burning as an early symptom, along with irritation of the nipple.
If you've already completed treatment for breast cancer, it can feel very scary to experience pain in the affected breast or your other breast. Breast pain is usually not related to cancer, but new and persistent discomfort in only one breast may be of concern. This is especially true if the pain is getting worse without any clear explanation. Be sure to see your doctor.
- Spread of the cancer to other parts of the body: Pain caused by cancer itself is more common in people who have metastatic (or advanced) disease, in which the breast cancer spreads to other parts of the body. For example, if the cancer travels to the bone, it can cause pain in the back, hips, or other bones. Cancer that has spread to the brain may cause headaches. Severe back pain with leg weakness may be from cancer that has spread to the vertebrae of the spine and weakens the spinal column, which is known as spinal cord compression. If the cancer travels to the adrenal glands on top of the kidneys, you may feel a dull back pain. If it spreads to the liver, you could have pain in the upper right part of the abdomen.