I am (still
) feeding my 14 month old DC4. For the last month or so after a feed, I am having excruciating breathtaking, stabbing pains in one part of my right breast (lower inside quadrant). They started after a particularly vicious mis-latch, after which I bled for a few days.
He's having two feeds from that side in a 24 hour period, and the pains last for 3 hours afterwards. Unfortunately it's the side that is the milkiest and gets engorged easily and I have had repeated mastitis on that side with the other DC, so I'm not sure just stopping on that side is an option.
I don't think it's thrush as it's just that side, the nipple is a little cracked but not peeling or pink, DC4 has a clear mouth. I am trying to get him to latch properly but he does feel he knows better 
So what could it be?