Sore breast, help

Hey ladies... my daughter will be 10 months next week, I’ve EBF her from the beginning meaning she never took a bottle and we’ve never had any problems. Last night when I was nursing her on my right side I noticed I was pretty sore, I just thought maybe her latch was off, she has 8 teeth and sometimes her teeth dig in, didn’t think much of it. She also has a cold and has been nursing much more frequently for comfort. But all day today every time she nursed on the right side it’s extremely sore especially when she latches. Any ideas what this could be??? I don’t see any physical changes to my breast.