Something came out of my chest?

I've has this strange bump in the middle of my chest about the size of a pea, and today there was a small scab on it, and picked it off since I thourght it would sort it out. After removing the scab I squeezed the small bump and q strange bit of dirt looking thing popped out and left what was pretty much a hole that was bleeding. The thing that came out is about the size of a pea, and had been living there for two years or more. Can anyone tell my what this might be? Like a serious problem or something I don't need to worry about.