Feel lump but not on mammo or us

Melissa919

Not sure if I should post here. I'm 27 and felt something back in October. I brushed it off and kinda forgot about it. Last week I noticed it again and it felt bigger than before. So I went to my gyn which felt it right away(4cm) and ordered a mammogram and ultrasound if needed.

I had a mammogram and ultrasound today, and was able to speak to the radiologist. She said there was no visible mass and that the area could just be normal tissue since I have very dense breast. However there is a cluster of small calcifications and also mentioned lines(overwelmed and only remembering pieces of info).

She scheduled me in for a mammogram guided biopsy(I think that's what she called it). She also said that if the results come back normal that I should still see a breast surgeon.

I'm just feeling so confused. How do I and everyone else feel this big thing in my boob but it doesn't show on mammo or us? Why would I still need to see a breast surgeon if results are normal?