Costochondritis is an inflammatory process. Nevertheless, it usually has no definite cause. Repeated minor trauma to the chest wall or viral respiratory infections can cause costochondritis. Occasionally, costochondritis as a result of bacterial infections can occur in people who use recreational IV drugs or who have had surgery to their upper chest. Costochondritis can also be a feature of relapsing polychondritis, reactive arthritis, fibromyalgia, and injury.