That's great you don't have pain. But the swelling is odd. There is something called costP=ochondritis. https://www.webmd.com/pain-management/costochondritis#1 That does involve swelling in that area (or could). Normally there is also associated pain. People sometimes mistake it for heart issues. But it is inflammation inflammation of the junctions where the upper ribs join with the cartilage that holds them to the breastbone, or sternum. Not sure though since you have no pain. I would go to the doctor and have them take a look. Is that possible?