Diagnosis. After deciding to seek out a consultation with a doctor, he/she will first conduct a physical exam, during which the breastbone and the surrounding areas will be felt for signs of swelling or tenderness. The doctor will also pay attention to the rib cage and the arms, moving them in certain ways in order to trigger symptoms. Oftentimes, the pain or discomfort associated with costochondritis can be very similar to that experienced in heart or lung disease, gastrointestinal issues, and arthritis, so the medical professional will first conduct physical tests to rule those out. Although there a lab or imaging test to confirm this diagnosis does not exist, X-rays, MRIs, CT scans, or electrocardiographs may also be utilized in order to rule out other conditions.