I have the same issue when I lay on either side to sleep. The left side hurts more though. I've tried a pillow between my knees, but that doesn't help much. Besides a dull ache, it feels like whichever side I'm lying on, that leg (thigh, behind the knee & calf) seem to have that feeling of 'falling asleep'. It's SO uncomfortable to the point of pain. When I lay on my back, it's all fine. I'm a side-sleeper, but I guess for not much longer!