I wasn't sure where you wanted the reply about screening or lump. So I thought this would be ok.
I am 42,lump found via Mammo. I will add this. I have had breast pain on that side for 3 years. I had a Mammo right before I turned 40,negative for problems. They followed up with an ultrasound and a surgeon opinion. Nothing was found and was told it was fatty tissue or fibrous tissue? I don't remember 100. The one area I had the most discomfort was right at the nipple,this is where my largest mass was found. So has it been there and I was just sensitive? Who knows..