Its due to the nerve compression in the back region which increases as we sit or forward bend.
Next Steps
Go to a physiotherapist.. Ultrasonic therapy +IFT +Heating therapy +some strengthening exercises will be helpful for sure.
Health Tips
At home.. Rest +hot water fomentation +pain killer gel +no long sitting /standing /travelling /walking +no stair climbing +no cold exposure +avoid keeping anything in your back pocket+no cold exposure +no manual exertions +no weight lifting +sit tall.