As you have mentioned that you are used to working on laptop and now it's hurting.. kindly pls maintain a proper posture for working .. also you can use a lumbar roll while working on a chair ..
Posture correction is very important for pain relief
Next Steps
Pls visit a physiotherapist for the same who will in turn guide you about it and would also suggest exercises for back pain
Health Tips
Avoid any kind of slouched posture while working as it adds to the pain