Teach baby a comfortable latch-on. Are you allowing baby to put too much sucking pressure on the nipple, rather than the areola (the darkened area surrounding your nipples)? This is the most common cause of painful nursing and may be why you've encountered problems. You need to get baby to open her mouth as wide as possible. Use your index finger to depress her lower jaw. When her mouth is open wide, quickly offer the breast while ensuring that her lips and gums are putting sucking pressure above your nipple. This not only makes latch-on less painful for you, but allows baby to get the most milk.
Another problem may be that baby's lips are tight or pursed while she nurses. This can lead to sore nipples. Try the "lower lip flip," a trick my wife (a lactation consultant) used on our babies. Once your daughter is latched on, take your index finger and flip her lower lip outward. This, in combination with baby's wide open mouth, should increase your comfort and nursing success.
(Taken from
http://www.parenting.com/parenting/b...153457,00.html )