If you need to pump, make sure you have the right sized tunnel on your expressing kit. The hospitals often don't stock multiple sizes, and they don't always know how to tell if it's the right size. A too-small tunnel shredded my nipples, and on of them only finally healed up last week - at the 12 week mark! I needed a large on one side and the XL on the other, but was given a medium in hospital, with no mention that they even come in different sizes.

Painful damaged nipples = stressed and fearful when baby is going to latch on = poor let-down = poor drainage of breast = mastitis.

Best of luck!