I had sore nipple issues too... and I used Lansinoh.. Until I found out it made it worse!
My right one was sooo sore it brought tears to my eyes. I had to take a break... So I pumped. I was much better the next day.
Is he staying latched correctly through the whole feeding period? My LO liked to make it to where he was just sucking on my nipple. I then had to take him off and make him latch correctly.
Everyone else has given great advice too!
Oh, and letting the breast milk dry on your nipples too!