I don't think the cysts were that hard, but I could be wrong. I was doing some research on cysts of the breast and although they say most are non-cancerous, they said that cancer could hide behind the cysts. I know just to have my arm up against the area is painful. The doctor said they could drain it. I think I would much rather have it removed (not the breast, the cyst)
I don't think that you are being overcautious. If it is worrying you, it's better to have it checked and relieve your mind than go around for 3 months worrying about it. Were the lumps that hard to begin with? While it may be cysts, they may have become infected or something. I go by the motto better safe than sorry. Especially wtih that family history.