Sore breasts A few days after giving birth, you might have full, firm, sore breasts.That's because your breast tissue overfills with milk, blood and other fluids.If your breasts are engorged, your baby might have trouble attaching for breastfeeding.To ease sore breasts, put warm washcloths on them or take a warm shower before breastfeeding or expressing.Between feedings, put cold washcloths on your breasts.