Burning in breast

MrsRidge2005

For the past few days I've had this burning sensation on my right breast.  It's almost like I have a blister on the nipple but I can't see one there.  I checked DS's mouth to see if it might be thrush but I don't see any signs of it in his mouth.  Any ideas what this might be?  It's not so bad that I can't have DS nurse on that breast but I haven't had this before and it's uncomfortable.