Pain in lower right back above buttocks. Travels down leg. Knee pain shooting down leg when crossing legs. No knee swelling, full weight bearing.

Sciatica. It is very likely you have sciatica. The sciatic nerve can be irritated with by many things. Recommend NSAIDs, exercise and ab strengthening. Sleep and sit on hard NOT soft surfaces. If not better definitive treatment is medrol dose pak and/or PT. .