Ouch, help me?

The other week before I got my period I had super sore breasts and they grew a size up. 
I got my period and a couple of days after the pain went away and they went back to the size they used to be. After about a week & a half Without any pain or them growing about 3 days ago they started growing again and they became super super sore. More then they have ever been and they are growing. I'm not due for my period and I'm not pregnant. Does anyone know what it could possibly be?