ELI5: Why does our eyes burn when we open them but not if they're closed?

My eyes burn when I open them. The pain is gone when I close them. When they're closed I just feel pain. But I never have eye pain. I'm only 5'4" and 125 lbs. My height and weight is 170-180. I never get eye pain, so why does that hurt me? Is there some other reason?