I think it can be a little bit of a blocked duct going on as well. I had the white spot when I had blockages - not all the time but most of the time. Heat before a feed is good. See if you can feel any lumps (which could be tender) on your boob and give them a little massage then feed. Sometimes I have had the white spot and no blockage as well though. Barb might pop in and shed a bit more light