Calcification

I went to the doctors with a lump got referred and they did biopsy the lump was benign, how we they have found some calicificatiions which they want to check So I am booked in for another biopsy on 19th October , they said they don't think it's anything to worry about and it's just a case of dotting the I and crossing the T but I can't help worry about this as if it was so obvious It was all ok why so they need to check!