Bubble in your chest that doesn't move and is a very sharp pain?

On occasion, when I’m stressed or really tired, I’ll get a bubble that, for lack of a better description, lies about where the middle of the bra sits. If I breathe slowly and heavily, I can feel it shifting a bit and the pain subsides for a second or two, but it comes right back and doesn’t go away until I sip something carbonated and burp a few times. But it’s a very sharp pain; something I find impossible to not outwardly react to.

When I try to describe it to someone, it’s extremely rare that they know or have experienced what I’m talking about.

The only time I’ve seen exactly what I’m talking about somewhere else was an episode of The Golden Girls when Sophia has extreme indigestion, and she points to the exact spot, and she says she has a “bubble.” Like when it happens to me, nobody knows what she’s talking about.

What the heck is this weird bubble crap that is apparently so uncommon? What causes it? I don’t think it’s just indigestion, as when I get it, I often haven’t eaten anything yet. Does anyone else get it? Is it preventable?

I should note that if I get it twice in two months, it’s a lot. I’m talking maybe four times a year at max.