Breasts are made up of lobules (milk-producing glands) and ducts (tubes that carry milk to the nipple), which are surrounded by glandular, fibrous and fatty tissue. Sometimes, fluid-filled sacs develop in the breast tissue; these are breast cysts.
Breast cysts are common and harmless. It is thought that they develop naturally as the breast changes with age, in response to normal changes in hormone levels.
Some women just have a tendancy for them. Do you drink a lotof caffeine? That can exacerbate them.
I rarely drink caffeine. I was on a no caffeine kick when I noticed them. I stopped my birth control and they went away so I though and then I was able to feel them again. My doctor says vitamin E will help a bit.