Just as bad mate. I go exactly the same.
A lot of people don't understand when you tell them, I usually get the old "what's up with you, it doesn't hurt" from friends.
I used to go the same when I cut myself with glass too, something about the smooth cut would make me go. I've got over the glass thing now but needles, fook no.
I had a root block done a few months back (injections in lower back to kill pain to my sciatic nerve) because of a prolapsed disc. You have to be awake during the procedure as they stick the needle in an take an X-ray, then take it out and repeat until they think it's right. Then surgeon touches the nerve with end of the needle which you have to feel (hence being awake).
I was shitting myself about it and it's my worst nightmare, I ended up in recovery ward like a twat. I looked over to see a young girl who was recovering from a general and felt a right wuss. Any normal person would prob have just been chatting to th nurses during th operation but not me