Lump in breast and not pumping much?

ECT2012

My right breast has always been a bit of a dud, but recently it has seemed like it has caught up quite a bit when I pump once a day in the evening.

All day today my right breast has been getting hard and lump in between feeds - haven't gone any longer than usual to feed her, but now it's happening again and I'm hardly pumping anything. 

I'm trying to massage the lump out but it doesn't seem like much is happening - any suggestions?