Hmm, that's odd. Is the pain really kinda above your knee? If so you're not fit enough. Suck it up and you'll toughen up. I don't know your age if you're under 18 you could most likely be having growing pains. I didn't snowboard when I was younger, but playing roller hockey used to kill my knees. As for binding positioning, You shouldn't go over 30 with both bindings combined. I keep my front foot usually somewhere from 5-15 and my back 0-5 or keep both sides the same if you plan to ride switch but don't go over 30. If your front foot is 15 than your back shouldn't exceed 15. You shouldn't really have issues just try to set a position and get used to it?