What could be the cause of sudden severe breast pain in one breast 4 years after full hysterectomy?

Fibrocystic change: You may have a cyst in that breast or the beginning of one. Better get it checked.

Do you have ovaries?: 1. Blockage of a milk duct -- we make milk every day no matter what, even past menopause. Almost all milk is resorbed in drainage tubes=ducts except when breast feeding. Blockage from dried milk, small infection, or inflammation can cause severe pain as the milk is being pushed against the blockage. 2. 'fat necrosis' - a tiny blood clot that kills a piece of fat (not dangerous) 3. Infection.