I Have Occasional Pain In My Chest Area (nipples) With

I have occasional pain in my chest area (nipples) with periods of constant erection of them. When I try to press them in they hurt with some swelling noted directly underneath the area. The swelling abates underneath but comes back when the nipples become tender again. It reminds me of when you ride those rafts at the beach except I never noticed swelling underneath them but I was a child lol. Thanks for any advice Keith