These are two conditions that all breastfeeding mothers dread the potential of. Mastitis is an infection of the breast, and it causes flu like symptoms. It is often accompanied by a red, warm spot somewhere on the breast. It can start from a clogged duct that doesn't get remedied or from an infection that enters the breast through tears or cuts. If you suspect Mastitis at all, please call your medical provider immediately. Clogged ducts occur when milk hasn't been properly emptied from the breast. These are most common when a mother's supply is regulating and may not have milk emptied properly. You can pump to get rid of clogged ducts, but be careful not to overpump, as that can make the problem worse. Additional Reading: Surviving the Boob Flu