What causes cyst in your breast? is it really related to cancer? are they suppose to come frequently everytime you have your period?

Fibrocystic breast: There are still studies that will help us figure out exactly why some breast have cysts (very common), but for now, we think it's hormonal. This may explain why it is common that the cysts are more prominent around the time of your period. There is no increased risk of having cancer if you have cysts in your breast. But, if you notice a change in your usual "lumps and bumps", have it checked out.

Yes, period related: In fact, very few breast cysts are cancerous, especially at your age but you never know.Most are caused by hormonal changes which would explain why you get them around your period.The best time to have a breast exam is about 7-9 days after your period so that the incidence of feeling hormonal masses aren't as high.You can have a simple cyst,a galactocele, fibroadenoma,or fibrocystic changes.