I was wondering about morphine. Is it possible for a person to be "immune" to it's effects? I ask because I was in a car accident a long time ago and was given morphine in the ambulance and it had no effect pain-wise, nor did it get me "high" like I had understood it should (I know people use it to get high and the nurse said it would make me feel funny). Once again, I was in the hospital recently for a serious medical condition and was given morphine, and still no effect whatsoever. I felt it go through my veins when first administered through IV, but other than that, nothing at all.

I have a surgery coming up and really need to know, as I'm scared to death they'll use morphine or something just like it and I'll be in horrible pain!!