Breast pain on bottom of breast!

I am exclusively pumping, with latching sometimes (she struggles to latch but we still try sometimes and she will eat a little off of me before being topped off with a bottle), and I am experiencing pretty bad pain on the bottom of both of my breast. My right one is extremely bad.Basically I can’t wear a bra because it hurts. I can’t lay flat on my back because it hurts. Is this a clogged duct? I don’t feel a knot but it is tight and it hurts. There is a bit of a rash on each breast, the right is worse. But it looks like a heat rash. What could this be? I’ve used a heating pad on it