Re: bad mamography
There are lots of benign conditions which look "iffy" on these. I spent 4.5 hours this summer, getting the initial mammogram, then a special digital scan, and then an ultrasound before they said you're fine, see you next year. Next year, I just take the day off and bring a few books.
If you have fibrocystic breast disease or very dense breast tissue or a tendancy to grow benign tumors, it can be difficult to read the initial x-ray and be certain what you are seeing. That's why they'll order extra scans or tests or biopsies.