Can daily exposure to x-rays have any effect on a fibroadenoma or other breast tumor?

No. Fibroadenomas are not affected by x-rays. X-rays can have harmful effects on various tissues of the body, depending on the amount of x-ray exposure and over what period of time the exposure occurred.
Possibly. Daily exposure to x-rays does have the possibility of increases cancer risks. This is why it is important to learn safety when working around x-ray equipment.
X-ray. Daily exposure to x-rays can be very dangerous. It can cause cancer but I am not aware that it can change a fibroadenoma. Some cancers are treated with radiation. Of more importance, why are you getting daily exposure to x-rays?