Re: Out of the blue soreness
It sounds like you probably have a plugged duct. You might want to try massaging the hard spot in the shower or warm compresses and gentle massage before pumping.
ETA: Definitely make sure you are pumping at least as often as usual, you want to try to clear the plug out. Baby will be even more effective at nursing it out once you are back with him. Keep close watch for red streaks or if you start to feel achy or feverish. Plugged ducts can lead pretty quickly to mastitis.
“We are not put on earth for ourselves, but are placed here for each other. If you are there always for others, then in time of need, someone will be there for you.”