If you do this for long period of time, can change the natural curve of your spine and create tension at the joints and tight your chest muscles. This can lead a dysfunction and pain may appear. To avoid this, you can: stretch your chest muscles and strength your upper back muscles.
A mattress is a very important piece because you will spend 7-9 hours a day on it. Your mattress should be firm in order to support your back, if it is too soft your spine will be out of alignment at night and your muscles may will be sore in the morning, and after a while you may suffer from low back pain. If you are thinking on buying a new mattress, I recommend that you invest in one that will give you better support therefore better sleep and less pain.
Sleeping over your belly
This is the worst position to sleep because in order for you to breath you need to turn your head which can strain your neck muscles, and also it will increase the curve of your lumbar area causing tension on your low back muscles. I recommend that you sleep on your side or on your back.
Sitting too long
If you are seated at your desk all day, you should know that doing this can decrease the blood flow into the muscles and this ones can be tight and sore, so get up and move around for at least 1 minute every half hour to encourage a proper blood flow and give your body a break.
Slinging your purse, bags or backpack over only one shoulder may lead you to lean to one side to compensate the extra weight, this can strain your lower and upper back muscles and dysfunction can be created and as a consequence you may start to suffer from pain on your neck or lower back.
So remember that never is too late for break a bad habit, you just had to try and be aware about it.