It could be it starting or could just be that you need to express a bit more. I would find 15 minutes and warm the area and then express v thoroughly concentrating on massaging the lumpy bits. Feed your dc when you get home pointing nose towards where it hurts. Keep expressing regularly but just to relieve pressure not to empty completely as you need your body to get used to the change. If you continue to feel ill or have temperature see your gp. I had exactly the same problem a few weeks ago and that was the advice I was given -worked for me!
I think I might be starting with mastitis, my boob is really engorged and lumpy, I feel hot and a bit 'funny', not totally with it so to speak. I haven't got any pain yet though.
I came back to work this week and monday and tuesday managed without expressing. I was off yesterday as I don't work wednesdays and fed baby (9 months) as usual.
My left breast has felt hard since 10am, I don't know if i have favoured my right side throughout the night maybe. I didn't bring the pump today since I didnt need it on monday or tuesday. I just hand expressed into a wad of tissue in the loo but while I was getting a great flow in some places, the lumpy bits didn't produce any milk.
Am I being paranoid and worrying for nothing or could this be mastitis setting in? Is it too fast for that to have developed? I have had it before but that was after a period of a few days of favouring the other side due to thrush.