What does it mean when your nipples hurt and you have milk coming out of your glands?

Galactorrhea: Milk coming out of the nipples is called galactorrhea. White discharge is milk, which may be caused by breastfeeding or pregnancy. It can also be caused by excessive prolactin (sometimes caused by a pituitary adenoma), trauma, or medications. Talk to your doctor for a history and physical, though you also may need labs or imaging to find the cause.