I am a male, 51, not in the best of shape but historically strong and healthy. I have what feels like an extended sternum maybe 1-1/2" below and 1'2" above the bottom end of my rib cage. It is hard, not soft, and does not move. It does not hurt unless I push on it, hard enough to hurt anywhere else. But I can feel it pressing into my upper gastro tract (at the very outside, directly under the end of the sternum). My chest is usually tight and constricted (not always). It begins to feel like I need a strong breath, but I am not short of wind or panting or dizzy. It feels worse when sitting or lying and better when standing or walking. It does not keep me from sleeping (except for the worry). I can't tell if it is worse after eating in the evening, because that's usually when I'm relaxing in th chair.
I do not have an history of injury severe enough to cause any lasting damage in this area. I do not remember how long it has been but probably close to a year. It does not seem to be constant but comes and goes with the conditions I described.
I have not found any clear descriptions of these symptoms anywhere. I do not think it is costochronditis because it is not soft or moveable at all. It feels like an unwelcome wen on the wrist or something. Please advise.