Tmi! What is this pain?

Paige

Throughout my pregnancy my breasts have been sore but nothing that I cannot handle. Yesterday I was sitting in my living room (lounge/sitting room) and I went to get something off of my sister and I felt the worst pain in my nipple/breast. Ever since then my breasts have been very sore especially my nipples. I am currently 40w+2. Anyone know what this is? This is my first baby/pregnancy so i wasn't sure if I should worry or not. Any advice would be much appreciated.