sore nipples but no visible issues- advice?

Jackie • Happily married 35 year old lesbian in Berkeley, CA. After eight IUI's, expecting baby #1 in November!
Hi all! My babe is 4 weeks old. Breastfeeding has been getting a lot easier, but over the past few days my nipples have been super sore. Other than redness, there isn't anything visibly wrong. Baby seems to latch just fine. I also pump 2-4 times per day. Anyone have an idea of what the problem might be? And any treatment ideas?