So in the last day or so, I have noticed an area on one of my nipples has become really sore. First I thought it could be bruising as sometimes my boyfriend bites them pretty hard but there's not much of a mark, it's pretty painful and it's a little harder than the rest? Any idea what it could be? If it doesn't go in a couple of days I'll go docs. I did recently go to the breast clinic as I found some lumps in the same breast, these turned out to be lymph nodes and a cyst. Obviously there the doctor had a feel and didn't flag anything up with my nipple when I was there. I'm 19 by the way.