A bulge in the chest with pain can be caused by the following reasons: First, there may be a sterile inflammation of the joints near the chest, commonly known as sternocostal arthritis. Usually, there is swelling near the thoracic rib joints, and in severe cases, there is redness, swelling, and heat pain such as skin flushing and increased skin temperature. Second, there may be a swelling in the bone or soft tissue near the chest. If it is a bone swelling, it is usually hard and does not move. You can go to the hospital to take a local chest X-ray or CT of the chest to make a clear diagnosis. If it is a soft tissue mass, it is usually movable and the boundary is clear, the most common ones are sebaceous cysts and lipomas. The diagnosis can be clarified by local ultrasound.