When I sit on my knees and then stand on my knees I get dizzy, not just dizzy but my eyes hurt. What could cause the eye pain?

Tight muscles. Try to not tighten anything and see if you still get the sx. ? See a good physical therapist, and see if you can reproduce the sx.
Possibly sinusitis. Really this is not a common problem. There can be a vascular malformation, sinusitis or ? Would help to have more information.