Stick to this simple rules to avoid backache:
Save your back any sudden strain.
Regularly exercise and stretch to loosen up the back and strengthen its supporting muscles..
If you have to sit still for long periods, make sure your back is properly supported. Place a small roll in the arch of your lower spine - at waist height - to maintain its normal S-curve. Simply a towel, or cushion rolled up will do.
When lifting a heavier object, keep your back straight and hold the object close to your body.
Balance items you carry evenly on both sides of your body and hold them close.
Try to sleep on your side, with a little pillow under your knees. If you feel more comfortable sleeping on your sides, a pillow between the knees would help your back relax.