its most likely a clogged duct! I experienced this , but my red area was tender and felt as if there were a knot underneath. I would get a rag and soak it in really hot water and I'd massage the spot with it while I would pump and feed on that side (I had to pump that side more because it hurt pretty badly for her to feed but I hear baby gets the job done way better) the red spot didn't go away for a couple of days though.
well i think it's Def be a clogged duct. but honestly I don't think it's bad if it's not really sore. I would try a warm damp towel over your chest and massaging the area as well you could do it in the shower and try to hand express and massage. but if it's still not going away I would try to get in touch with your doctor about it just to make sure it's not serious. lol I only breastfed for 2 months. so I guess I'm not the expert at it really. but I Def remember those lumps. hope it gets better girly!