Focus on correcting your posture, use a pillow for lower back and a foot stool to elevate feet especially if you sit for long hours. Take permission from your doctor and sign up for a Prenatal exercise class to learn back exercises.

thanks Nidhi will definitely try it.

thanks prithvi but it's very difficult to sleep all night on left side. trying my best.

Take rest sit with a support to your back with a pillow and sleep only on your left

try hot water bag