Sternum pressure/snapping when pushed

I've seen the many sternum issues posted here but I don't see quite the same as my experience and wondering what I'm dealing with. I will develop a pressure located right below/under the sternum or V of the rib cage which I can feel a ball or lobe-like thing inside when I push, a discomfort, sometimes it is more than others, sometimes not at all. If I push on it either straight on or sometimes to the left or the right, it will snap once or perhaps a couple times and the pressure goes away. I can feel the pressure kind of in the middle of my girth, I won't say it goes to the back, at all. The pushing/snapping will not always releive the discomfort totally. Sometimes I don't snap itt at all in a day, and others it is nearly a continual routine without my even realizing it anymore. Comes and goes but more frequent than before. Any ideas?