I had my baby two weeks ago and I have a blocked duct lump on one of my breasts about the size of a 20p. I was prescribed anti-biotics, been feeding regularly from it, had cabbage leaves in my bra and have tried to massage it out. It is still there! Will it ever clear - it is really starting to worry me that it is going to be constantly infected and ruin the feeding.
one thing I found helpful when I got blocked ducts in the early days was feeding with the affected breast hanging down (so with the baby lying underneath you and you on all fours above - sounds weird I know! ) as I'd read that it could drain better that way, its a bit awkward but it seemed to work for me.
have you spoken to a bf counsellor/gone to a bf group? they may be able to help.