Hi bloop123,
I also have a lump on the breastbone and swelling of the costal cartilage of the 2nd rib on the front of my chest, as well as my right sternoclavicular joint. Mine's been there since March '12 (June for the SC joint). I think what you may have is similar to costochondritis but it's called Tietze's syndrome. The main difference is that it causes visible swelling. It most commonly affects the sternocostal junctions of the 2nd or 3rd ribs or the sternoclavicular joint. It's a benign inflammation of the costal cartilage. From what I've read, they don't totally know what causes it, but injury, physical exercise, upper respiratory infections and inflammatory autoimmune conditions may contribute. You mentioned a chronic cough - I've read that coughing can cause trauma to that area, so that may be what's irritating it and causing the inflammation. It's good you're getting thorough tests run - I hope you feel better soon!
Post Edited (fwdmotion) : 10/18/2012 6:37:55 PM (GMT-6)