It is all about if you sleep on right side. Most of us have a side we prefer to sleep on. Yes we move around in our sleep but there is usually one side we continually fall back on. And if we are lying on your right side is your fail safe side. you might want to rethink your positioning.
Sleeping on your stomach is the wrong and worst position. Sleeping on your back is the most recommended because the vertebrae can align your back naturally in a neutral position without any kinks or curves.
Sleeping on your back may be healthier for your spine whereas sleeping on your right side is beneficial for your heart.