The swelling of the rib cartilage under the breast is not normal, and it is suggested that the patient should go to the regular hospital for examination first, which may be the manifestation of costochondritis, breast hyperplasia and tumor. 1. Costal chondritis: mainly manifested as enlarged and elevated rib cartilage area, limited pain with swelling, fixed pain point, obvious pressure pain when pressed; deep breathing, expanding the chest wall and other actions will cause pain when the thorax is overactive. 2. Mammary hyperplasia: with breast pain as the first symptom, there may also be breast nodules or lumps, and some of the patients may have pain in the chest involving the rib cartilage of the patient, which may cause swelling and other discomforts. 3. Tumor: the swelling of the rib cartilage under the breast does not exclude bone tumors such as osteochondroma, osteoid osteoma, etc., which may cause the formation of lumps on the rib bones, thus triggering the swelling of the rib cartilage under the breast, and it is recommended to do a CT or X-ray examination to check for related diseases. This symptom alone is not enough to diagnose the disease, and may be caused by other factors, such as trauma. It is recommended that the patient consult a doctor to determine the cause of the disease and provide targeted treatment.