Any idea what this shoulder "button" is?

[divingbiker]

Before I decide to go to the doctor about this, I thought I'd see if any of you have any idea what this weird bump is on my shoulder. It's about the size of a button, and there are two of them close together under the skin. I've attempted to take a picture, but it's a little tricky to operate the camera at such close range with my left hand. If the big mole is at the center of a clock, the button is at about 8 o'clock. Thanks!