If your breasts feel heavy, sore and hot, it is because they have been congested. This is because you have too much milk in them.
Breast congestion during pregnancy
In general, breast congestion usually appears during the first few days of birth, when the milk begins to fall and some babies do not light up very quickly to the chest.
Over the days that intake of milk by the newborn is normal and is done regularly, congestion usually goes away by itself. But it is worth a few tips to ease this discomfort so common in new mothers.