Hi i recently fell off the back of a chair and hit the back upper part of my head on the bottom of the chair. i was fine did not black out or anything. but two days later i feel pressure in ears/temple/front like sinus pressure?

May be consequential or coincidental sinus issue, such as infection. Sounds like head injury was not concussion, and unlikely to be the pathway to brain or headache complications. Would help to notify your doctor as this may herald the onset of a sinusitis?

Consider a jaw joint injury. Normal jaw motion is 12-15mm lateral motion left and right without pain.