I recently came across this post as I suffer from similar knee pain while hiking downhill or on a run.
Also be certain you aren't battling other imbalances of the hips and legs. When you lay down, do your toes turn way out to the side or point straight up? If they turn to the side(supination/external rotation of the knee), your hip abductors are too tight while your adductors are too weak.
I never paid attention to the way my feet rests while sleeping. I sleep on my back with my feet turned out. My feet make a 180 degree angle i.e. the outside of my feet completely rests on the bed. Is this normal? What problems could this give?
Should the feet be pointing straight up while sleeping?