I also had same problem. My mistake was I stopped using puller after few days which resulted in Sore and damaged nipples which needs extra care and lot of patience. It took a month for me to heal completely and feed baby without pain. I also ended up having engorged breasts with lump and mastitis infection.
Use nipple puller or breast pump for few seconds or minutes b4 feeding and ensure proper latch.
U shud hold baby by neck, hold your breast on the other hand and when her mouth is wide open, push gently onto your breast. Baby's mouth should be around the aereola.
Seek your husband's or mom's help if needed.
If you dont follow this, you may end up having sore nipples.
Make sure to apply some breastmilk on your nipples after every feed.
Be patient and don't stop breastfeeding.
My baby is now 60days old and is able to latch without a puller.