It is really common but usually it's not severe and goes away within 2-3 days (if noise-induced).
Tinnitus Talk Support Forum
I think it's all about genetic predispositions, maybe even genetic trauma, some theories even point to decreased contraction-treshold brought on by a lifetime of bad posture. Some people are just most susceptible for this than others, like it is with almost anything
With that being said though, tinnitus actually seems to be pretty common. Since onset I'm finding out that almost half of my friends have it
There are deaf people without tinnitus, this is not just hearing.
I believe when they figure out how to stop the tinnitus in the brain, we'll all be fine.
Don't get into my head people having the same problems as us and not having T.