Everyone knows that good posture is important when sitting / standing but it's just as important to have good sleeping posture. Whilst you sleep, your body starts to mend itself and this can be restricted if your body isn’t in the most comfortable position.

Why it is important
Strain is not good for your neck and back whilst you sleep. If your pillow is too low or too high it can stretch your neck in uncompromising positions. This can have adverse effects when you wake up with a kink in your neck and back pain. The most common sleeping position is the side sleeper and it is common for people to not have the correct sized pillow under their head which causes problems. The important rule is to align your ears, shoulders and hips. This will make sure that the normal curvature of your spine / body is correct and not out of place. This means when you move position you still need to keep these aligned for proper back posture.
Upgrade your bed
Memory foam mattresses and mattress toppers are also a good way to gain more support whilst sleeping. With the increased support, it will cradle your body into positions that will help your back rather than hinder it. Instead of a hard mattress that offers now give, a memory foam mattress will take the pressure off and give you a bit of suspension when moving around in bed. If you're a bit of a freestyler sleeper and move around a lot, it is hard to keep everything aligned whilst being asleep, so having a mattress topper can give you some support without having to align everything everytime you move.