Does anyone know what these bumps on my chest could be? (Possible tmi)

So it started out as one red bump at the top of my one breast, and had increased to a lot. They started on the top of my chest, but now they are also on my shoulders and a few on my ribs. I'm making a doctors appointment tomorrow but I'm so confused... they are just read bumps that aren't even really bumps, and they don't ich or hurt... I don't know what's going on