I also have fibrocystic breasts. I no longer get my period, but when I did I was in a great deal of pain as you are. Cutting down on caffeine intake helps somewhat. There's not much you can do because it's a hormonal thing. I've heard that taking vitamin D will help, but I'm not sure if that's proven.
Good luck to you; I hope you find some answers.
Dear blufgal: Breast pain is very common, particularly around certain times during the menstrual cycle. You may want to seek the advice of a medical breast specialist (these are often affiliated with large academic medical centers) with regard to how best to manage the discomfort. Our expertise is breast cancer. Most breast cancer is not painful.