This only happens to the passenger side, recently been to an accident before i bought the rex. right when i drive it for a while, it drives normal but after like, 20 min it starts to clamp on the brake disc and shakes while driving. what could this be?

 

Explain more about the accident. This sounds like a bad brake caliper. Replace both front calipers because if one is failing, the other could be old or in poor condition as well. Just my guess, its kind of difficult to diagnose over the internet.

 

or a weak brake line