Mastitis in an infection in the mammary glands in your breasts. It's most common when your breasts are engorged within the first six weeks right after birth. But there are other causes beside engorgement-tight bras, tight shirts, underwire bras and sometimes just baby laying different when they nurse.
And it hurts like a son of a gun. You can go to the doctor and get antibiotics, or you can stay home and treat it at home-without $150 doctor fee and $100 antibiotics :/.
To treat at home, you need all the immune boosters you can think of. Vitamin c, elderberry, echinacea, garlic. Cabbage leaves in your bra help (don't ask me how, I just know they do). You need to express milk while putting pressure on the sore spot to get the clog out. When baby nurses, point baby's chin or nose to the infected area (it will be bright red) as best you can and nurse. Warm compresses (wet wash rag heated in the microwave) against the area while baby nurses helps a lot. Time and sleep. It will hurt bad while baby is nursing, but it's the best way to get it out. The doctor will tell you stop nursing on that side-but I speak from experience when I say it just makes it last longer.
I, at the very least, have a clogged milk duct.. Probably from Grace playing acrobatics while nursing lately. I have a slight fever, can barely stay awake and just don't feel good. Hope this helps somebody.
I've been told cabbage leaves can help, though they can also dry your supply so you need to be careful with using them and how long you do so. If it is really bad and not improving, contact your doctor. It could be an infectious type of mastitis that causes an abscess. I know someone who got an abscess and had at least 3 surgeries - it sounded horrible. She is still breastfeeding her daughter at 7 months!