I don't think it is. Usually, movies or stories like 'Shut In' are crafted from the imagination of the writers and filmmakers. They might draw inspiration from various elements but aren't based on real events.
Not all of them. While there are numerous free on line short stories available on platforms such as Smashwords (which has a lot of independent authors offering their works for free), there are also paid short stories. For instance, some well - known authors may sell their short stories on their official websites or through major e - book retailers. And in some cases, you might need to subscribe to a service to access a library of short stories, like with Scribd.
I'm not sure which novel you're referring to because you didn't provide any context or relevant hints. If you can provide more information, I will try my best to answer your questions.