When you hand express are you pushing on the boob part only? Not the areola? Can you try hand expressing from the top down towards the areola but don't go that far? See if that is less painful?
A pump defo shouldn't be hurting you, I used to find it a bit of a weird sensation though, but only for a moment.
Only other thing I cna think to do is sit in a warm/hot bath and your boobs should start to leak quite a bit, that might help relieve them a bit.
xxx