Can I refuse to have a iv put in

Depends on what it's for sometimes they give you an option if you want to refuse treatment other times of it's life or death they take your option away

I wouldn't but I know it hurts. You should have seen the bruises on my arms the last time I was in the hospital. I wanted to punch one of nurses.

You can request them to inject a local anaesthetic on the area in the subcutaneous tissue with a 1cc needle before administering the actual IV. I've seen doctors do this especially if they must secure IVs with large bore needles

Yes but why would you ?

What if you are really dehydrated?