Michelle,

If the breast cancer cases in your family are in women under 40, you might want to ask your doctor about genetic counseling to see how elevated your personal risk for breast cancer is.  Many women overestimate their breast cancer risk and there is no need for undue worry.  If your risk is high, there are some risk reduction measures you can take.

Cysts are very common in women in their 30's and 40's.  They diminish in frequency after menopause.  You can rest assured that an ultrasound finding of a harmless fluid-filled cyst is highly accurate.  Cysts are often tender and/or painful while cancerous breast lumps usually do not hurt.

Calcifications are also common although I'm not familiar with the age range when they typically appear.  Scattered calcifications are not a danger sign.  When calcifications form a tight pattern, doctors sometimes want more imaging tests immediately, sometimes, want more frequent mammograms to monitor changes in the pattern of calcifications, and sometimes want to biopsy just to make sure that all is OK.  It sounds like your doctors are on top of this situation.  Continue to follow their recommendations.