I had an episode of reflux aspiration many years ago. I woke up and could not breath. It took me almost a minutes to get air out and back in. Some people inhale the acid reflux and get lung inflammation and a cough. It is all very serious and needs to be addressed immediately. You can experiment and sleep upright in a comfortable chair for a few nights and see if you improve. Your bed needs to be elevated 8 inches, you can use old books. I discovered a way to strengthen the lower esophageal sphincter. It is described here: