Danger to self, Danger to others and grave disability are the grounds for involuntary hospitalization. Parents can place their kids in a hospital under some circumstances.
If you are harming yourself, then something is very wrong. It could be a neurological or even physical problem that is fixable. If you have PTSD, your symptoms may be related. Many people get treatment in the hospital and come away much, much better over the long run. Those that have been traumatized
often don't know how to heal themselves. Help requires others who understand.
Wouldn't it be better to have someone other than your parents figure this out. They could use some help so that you aren't so miserable. I'm sure they are hurting watching you in pain. There's no fault here. Go talk to an adult who knows about these things. A therapist or doctor would be a good choice.
Been there, done that.