Summarize:

Sleeping on your back keeps your head, neck, and back in alignment. It can also help prevent pains in your neck and back as well as help with conditions such as acid reflux and heart problems. However, if your preferred sleeping position is on your side, you can use a body pillow to achieve similar results.  Body pillows conform to the shape of your body, which helps align your spine in a more normal way. It also provides extra support, which helps relieve back pain and stress. This causes you to breathe easier, promotes better circulation, and aids in muscles relaxation. Side sleeping with a body pillow can help you if you have sleep apnea, a condition where you stop breathing then restart breathing while asleep. Body pillows can also help you if you snore and if you are pregnant Sleeping on your side while pregnant helps improve blood flow to your uterus and can help with ankles that are swollen. It also supports your neck, back, and belly at the same time. Sleeping on your left side is generally considered preferable if you are pregnant. If you develop back pain after you start using a body pillow, stop immediately. It should not cause you any pain or discomfort. If the back pain becomes common, see your doctor or a chiropractor. If you start using a body pillow to help back pain and it gets worse, stop using it until you can discuss your options with your doctor.
Learn how body pillows help. Know other reasons to sleep with a body pillow. See a chiropractor.