What Causes Painful Cyst On Outer Ear Bone?

hi, every few months or so i develop this painful cyst like pimple on the outer bone of my ear. I know that i shouldnt pick at it or dig at it at all, probably, but its weird; it just start to hurt, gets inflamed, weeps, probably from me picking at it! But it really hurts, and i rarely, actually only once have i succeeded to get a hard like white head out of it. I treat it with polysporn and with time it usually goes away; but it always comes back, it only happens in my right ear and has been going on for a few years. What is it, and what should i do?