I had a blocked duct a few months ago, so a similar time to your DS. I was trying and trying to massage it out but no luck. Then while i was massaging in the shower i realised that there was dried milk in the nipple. When I got that out with the aid of the hot shower and nipple massaging the milk could "run free" and that saved the day. It was so painful, and no wonder since the milk could not escape the nipple and all my massaging was doing was... well nothing. So check out if you have a blockage at that point.