Back pain can be really tough as your body changes. Try using a proper feeding pillow or a maternity pillow between your knees while sleeping on your side, it really helped align my posture. Also, avoid lifting any heavy things.
I had terrible backaches even after my C-section, so I completely understand. Sitting with good lumbar support and using a hot water bag on my lower back really helped soothe the muscles. Just make sure the water isn't too hot, and rest as much as you can.
Hey, don't push yourself too hard, back pain is just your body adjusting to the baby's weight. Try sitting with your back straight and use a small stool to elevate your feet while sitting. If the pain is very severe or doesn't go away, please let your doctor know.
When I was staying with my parents, my mother used to gently massage my back with warm mustard oil. It was so relaxing! Just ensure you don't apply too much pressure on the lower spine, and always sleep on your left side.
Gentle stretching and light prenatal walks can do wonders for a sore back. I made sure to stay active during my pregnancy, which really helped during my normal delivery too. Just check with your gynac once before starting any specific exercises.