Hugs hun, its so frustrating when they aren't feeding properly! I have had mastitis twice in the right boob and my milk on that side was salty until the infection cleared completely. I also noticed my let down on the affected side was slower than normal for a few days after. Have you tried expressing to the point of let down then offering it too him? I found this worked for DS2 cos he was getting frustrated and pulling off before the let down happened.