You can try to use maternity pillow, lay on either side or use cushion/pillow as support. When you do chores, heading out, etc remember to use maternity support belt. You can do some light stretching for pregnant mummy and learn to maintain good posture. You will feel back pain during pregnancy due to baby growing and your body preparing for labour.
you can try using a birthing ball or a gym ball and sit on it. do some minor exercise with the help of the birthing ball to ease your backache. It actually helps me to cope with my backache.