I need info on causes of costochondritis?

Pain rib/cartilage. Costochondritis is an inflammation of the cartilage that connects a rib to the breastbone-sternum. Common causes are : injury & coughing and rare causes: rheumatoid arthritis, infection, & tumor. Costochondritis occurs most often in women and in people older than 40. See also http://www.Mayoclinic.Com/health/costochondritis/ds00626.