should I be concerned

I recently went for my annual mamgram and a mass was discovered on my right breast. I was given another mamogram (mammogram) of just the right breast followed by an ultrasound. After the ultrasound, I was told I needed a biospy. I didn't feel a lump and neither did my doctor during my routine examine. I am not sure if I should be concerned, I read somewhere that 85% of most biospy turned out to be nothing and that the likelihood of cancer is very slim. My maternal grandmother had breast cancer and so did my first cousin, I not sure how much family history plays into it.

[Cleveland Clinic]

Dear jojoreading, Decisions about need for further investigation (such as a biopsy) of a finding on mammogram and/or ultrasound are based on how suspicious the findings are to the radiologist/doctor who are viewing and interpreting the films.  Over the internet without ability to view or know the report of the testing it is impossible to say more about degree of suspicion of the findings from your individual tests.  Your doctor would be better able to discuss the need for a biopsy in your individual situation based on the testing results.