Breastfeeding help (not sure where to post)


My son is just over a week old and I’m breastfeeding. A few days ago I started to notice pain in my left breast while he’s eating. Now he prefers my right breast to my left and it has become engorged. I have a pump but haven’t used it yet. What could it be or why?? I plan on seeing a lactation consultant this week. Can I pump my left breast so it’s not as engorged?