swollen armpit!

Ashley
I'm 32 weeks pregnant and my armpit started to hurt quite badly about three days ago. Today it kinda felt swollen and extremely painful just to put my arm all the way down, and move it normally. Tonight I actually had a chance to look at it and notice it is swollen! I know there are milk ducts that go into the arm pit. But has any other expecting mommys exprience this? What is it? How do I make the pain go away, and should I go to the doctor?