The burning sensation caused by acid reflux can keep you up at night. I learned this uncomfortable fact when I was pregnant.
If going to bed after eating too much or having a spicy dinner keeps your tossing because of indigestion, the solution might be as simple as lying on your left side. The esophagus, aka food tube, curves slightly as it connects to your stomach. Sleeping on your left side creates a sharper angle preventing the burning stomach acids from escaping into your esophagus and creating pain. Try it next time acid reflux keeps you lying awake at night and see if you can make your body angles work for you.
Another trick for dealing with nighttime heartburn is to elevate your head four to six inches. This steep angle keeps stomach acids flowing in the right direction.
Good night, and good luck!