Hi Helen,
I am not sure about c/sections but did have the gas for my vaginal birth as DS was in a posterior position. IMO It doesn't seem to help with the actual pain but does help your mind drift away a bit (the kind of feeling like if you get up too fast and your head goes a bit funny). The thing I found though is it gave everything a bit of a nightmarish quality and I am not sure if I could cope with that for a c/section.
I hope your OB can help so this time around doesnt hurt as much.