I have a Medela PIS and just started pumping yesterday. I find I can only tolerate up to a 3, sometimes only up to a 2 if I'm pumping to empty after LO has already fed on one side (I have a clogged duct). I have had nipple soreness due to shallow latch so I don't know if this is why pumping hurts so much, but I know I'm going to need to get up to 5 since I'll be pumping when I return to work in 10 weeks.

Were you able to tolerate pumping at a higher pressure right away, or did it take you a while to ramp up to it?