Yes it is scripted and most of them are really cheesy storylines, which is one of the reasons I watch it, because the storylines are funny and it is supposed to be entertainment after all.
The injuries these athletes suffer during their careers have long term affects on their lives and to us it probbly makes us wonder if it's worth it, but to these guys wrestling is in their blood. The passion that these guys have for what they do usually comes down to the fact that generations of their own family have wrestled before them.