1.Not to sound like a smartass, your arms should be holding the bar in place on your back?
2. What do you mean, where is the pain located? Where are you holding the bar? Is it shoulder pain?
3.I think I know what you mean by something like this:
I typicially don't have a problem with those racks, once again where on the bar are you hands? I only ever have a problem when I take a snatch grip width.