Is it possible that I have fibrocystic breasts due to excess caffeine?

No. Fibrocystic breast condition is a description of your breast tissue. The composition of your breast tissue is determined genetically. It is not caused by caffeine intake. However, there are some studies that suggest caffeine intake can effect your tissue resulting in increased breast tenderness.
Maybe. Women's breasts have some lumpiness naturally -- they contain all kinds of glandular, fatty, and connective tissues. Some research shows that eliminating caffeine-containing beverages and foods (such as coffee, tea, cola drinks and large amounts of chocolate) can help fibrocystic breasts. Not all research supports this though. It could be worth a 4-6 month trial off caffeine, to see it it helps.

Related Questions

Fibrocystic Breasts 15+ years. Can't take hormonal BC (stroke risk). Vit E/Primrose/massage/no caffeine/diet no help. Other options for managing pain?

Good breast support. Unfortunately, there isn't any magic pill or method for you to alleviate your discomfort except one- Get fitted for a superior brassiere that can support your breasts which can eliminate the pain of "bouncing". If that is not affordable, consider an inexpensive breast binder for those more difficult days. Read more...