Did caffeine cause fibrocystic breast tissue to worsen?

Yes, in some. For many women, caffeine intake (coffee, chocolate, soda/pop, tea) can make fibrocystic changes more active (pain and lumpiness). Natural hormonal changes or hormone intake can cause this as well. Stress is a big offender because it causes us to release more of our natural hormones. Try decreasing caffeine intake and reducing stress. If no relief, contact your doctor.