Bruising post op...

I noticed about 3 weeks post op that I had a very yellow bruise on the front of my left breast, about 2” from the center of my chest. It caused me concerned because I had not noticed this before. And since it was yellow, that means it was healing, and had had a worse bruise prior to it being yellow. I had not noticed a bruise on my breast, I think because I was so focused on taking care of my incisions daily. I’m wondering if this may have happened when I was in surgery. It did take the yellow bruise a good two weeks to go away, and then tonight I noticed a lump in my breast in the exact spot where the bruise was. This is really scaring me, but wondering if anyone else has had a similar experience??