Back ache can be due to several reasons. It can be muscular, related to disc degeneration or prolapse, joint irritation or nerve pinching. Most common is muscle pain due to tight and weak back and abdominal muscles. Keep a positive attitude, focus more on keeping good posture
especially when sitting for long hours, use lumbar support. Take frequent breaks and stretch in between. Try changing sleeping habits. Try hot or cold therapy as tolerated. Wish you speedy recovery.