Hi 小Panda,
From my friends & my experience, you won't feel painful when 剪陰同聯針 because all your attention will go 陣痛 & get yourself ready for delivery.
But it's true that it's quite painful when 陣痛. Pls bare in my mind & be confident that you can overcome because everyone can do so. Pls remember just after a while, a lovely newborn baby will come.
Add oil!