as has been said, needle in quick, stuff in slowly

i found doing my own injections helped me to stop any pain - if it started hurting, i just backed off on the injection - others can't read that for you. i had a few times the nurse injected stuff for me cos i was there and had to have them at that time - and those ones always hurt more! maybe get DP to do her own injections for a day (you still help get it organised so you're a part of it) and see if it is less painful for her