Perhaps I'm naive but I think few people pretend to have that kind of pain. They do indeed have it. It might not arise from a truly traumatic experience but when somebody is under stress they do often react badly to people seen as threats. And people under stress see threats everywhere.
> It might not arise from a truly traumatic experience...
If it is not from life threatening situation it's not PTSD, it can be a serious case of anxiety disorder but you shouldn't confuse those.
It's an interesting question. Is a traumatic experience created in your mind different from one that occurred in the natural world. On the surface perhaps but on a neurological level I don't know.