What is this pain in my chest?!

What is this pain in my chest?

I occasionally get these very sharp, shooting-type pains in the left half of my chest. When it happens, I can only take very slow, deliberate breaths, because if I breathe too quickly, the pain shoots again. They're really quite painful.

I've heard other people talk about similar experiences, calling them "heart catches" or some other non-descriptive term. They've said that it may be a gas bubble passing through my heart. I wouldn't know.

I'm not 30 yet, so I assume it's not heart disease or anything. Does anyone know?

Thanks

You need to go to the doctor. People can still have heart problems in thier 30's. In fact there is a form of angina that happens at rest associated with smoking because the heart arteries get smaller, rather than blocked, which happens in heart attacks and angina pectoris. Could also be costrochondritis, pericarditis, or pleurisy.
Based on what your describing costrochondritis is a good bet, but all chest pain is cardiac until proven otherwise, meaning you need to be evaluated.