Lump in breast, but US came back clear . HELP

I have had a painful moveable lump on my breast. I went and saw my OB and he felt the lump and suggested it was a cyst and ordered an ultrasound. Went to get the ultrasound today, the tech felt the bump but the radiologist said they saw nothing. Nothing that says a cyst, cancer, or anything. I got my IUD removed in september. They said it could be due to hormones and I have dense breast tissue, I’m only 20. But i’m so confused. It hurts and I have radiating pain at times. Never felt this before.

What do you guys think? Is the lump hidden behind tissue? Is it nothing to worry about?