Routine breast MRI are not generally done even in patients with your history (papillomas and atypical ductal hyperplasia). One of the reasons is that it tends to be too sensitive and picks up a lot of stuff that the doctors don't know what to do with. So, of course this leads to alot of biopsies. The vast majority will be negative.
The reason you didn't have a breat MRI to begin with, is that it is not the community standard of care. So I'm actually not sure what it was ordered in the first place? Regardless, don't worry, I know it's a hassle, but like I said, the vast majority will be negative. "Irregular heterogenious clumping with washout" could just mean hyperactive breast tissue (fibrocystic changes, etc.)