Oh my! Absolutely! I can never sleep on my back. When I fall asleep flat on my back I often have episodes of sleep paralysis, where I seem to wake up, but cannot move, feel very panicked, and want to scream but can’t, and am still asleep somehow, but it feels very much as though I’m awake. This never seems to happen when i lay in a different position, so I just avoid sleeping on my back now. Also, if I wake up but stay lying flat I will feel as if there is a lump in my throat, and I will feel nauseous, but sitting up seems to help. It will lead to vomiting on the odd occasion, and is much worse if I don’t get enough sleep, and the sleep paralysis is also worse if I’m over tired.