Re: I'm in sooo much pain
If after a feeding the lump is gone, I would encourage you to put a cold compress on it instead of warmth. Warmth promotes blood flow which in turn promotes more milk production in the area. If you put something cold on it (bag of frozen peas or something) it will inhibit the blood flow to that area. Don't do it for too long (15 minutes or so, make sure you cover it with a cloth to prevent skin damage).
you can also try changing positions on that breast. They say that wherever the chin points is where the strongest sucking is, so to fully empty that side, position baby so his chin is where the plug is.