About two to four days after giving birth, your body will begin to release the milk-producing hormone prolactin, causing your breasts to become swollen, hard and tender to the touch. While it can be painful, engorgement is a sign that your body is ready to produce the milk your baby needs. OB/GYN Erika Lynn Nichelson of Mercy Medical Center in Baltimore says that women should breastfeed often or pump regularly to prevent engorgement from reoccurring. "Sometimes, however, it is unavoidable," she says. The pain from engorgement should subside a few days after you begin breastfeeding and should completely disappear once your infant’s nursing routine is established.