pain on one side

Whitney
Hey ladies! 2nd time mom first time breastfeeding. My daughter couldn't latch so I exclusively pumped for her. My son is doing well this go around. Praise the Lord! However, something is going on with the left nipple. It's extremely painful while and after he's nursed. The right side is totally fine? I don't feel like it's a plugged duct but I don't know for sure. Any guesses or ideas on things to try would be appreciated.