I have a hard bone like lump on the upper left side of the middle part of The sternum. I practice mma and i think it is the cause of it, when exactly im not Sure. But i have difficulty doing things such as bringing my elbows close together or doing a pushup. Ive popped it a couple times by tilting my neck back and it seems to alleviate some of the pressure but any weight down on my cheat does alot of pain. What can this be? YYYY@YYYY thank u