During pregnancy, nipple pain is generally caused by hormones. By contrast, if you notice nipple pain in the early days after your baby is born, you should assume there is a problem in need of a solution. Although nipple pain in the early days (usually peaking at 3-7 days postpartum) is common, it is not necessarily normal. A common problem leading to sore nipples is an ineffective latch. Although you are experienced with nursing, your newborn is not, and you will need to find your way together to the best latch.
The sensation of fullness when the milk “comes in” is likely to come earlier for you now that you are a second-time-mom. This feeling of fullness is believed to be a sign that your supply has just begun to exceed demand. From here on your body is prepared to make milk in proportion to your children’s demand (plus some extra for good measure). Tandem nursing moms can make as much milk as mothers nursing twins.
Engorgement is a common problem in the early days for mothers whether they are tandem nursing or not. The most important thing you can do to reduce engorgement is to ensure that your baby has frequent opportunity to suckle at the breast. As a tandem nursing mother you have an ace in the hole: your toddler! Your toddler’s nursing can relieve engorgement, and a less full breast may also be easier for your newborn to latch onto.