It can be due to back muscle weakness as well as the nerve compression at the back region which leads to radiation of pain the hip and even the leg also.
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 /driving +no cold exposure +no manual exertions +no cold exposure +use cushion support while sitting +no forward bending of back.