Anyone experience this?

I have a history of dense breasts with lumps that come and go, my breast has always been lumpy. After 35 I had my last baby and they deflated but the upper area was still more dense , I also workout so I’m guessing some muscle there too. 6 week post partum dr said they felt denser and asked for us and mammogram. Had it done and ultrasound tech said she saw absolutely nothing but mammogram picked something up in the left that she said was 96% chance of nothing. Had me come in 6 months took many many pictures and said it was clear to come at 40 or if something arised (I was 35)
This was August 2025, after a few months I noticed my left breast upper outer quadrant felt denser, bigger. But it was super movable so I brushed it off to it being tissue.
Now it’s july 2026 almost a year later I went for an annual obgyn app with a different obgyn and told her about the left breast she felt it and said she does feel a mass, 4cm, moveable, soft and tender to touch. She said both breasts are modular. I’m dying with anxiety because I have to wait 4 days for the scan. Anyone had this happen and was nothing? I’m so scared!