What Causes Pimples On Breasts?

Hi, I discovered a pimple like thing on the skin of my breast. It was hard and there were actually 2 holes (pores I guess) on either end of it. It was kind of elongated. I squeezed and the tip of it popped out, I squeezed some more (absolutely no pain) and a yellowish booger looking thing came out, very hard feeling. Now my skin has 2 red dots (that bled a little) and looks like I was bitten by a small vampire. Was this a pimple or clogged pore?? anything to worry about? THANKS!