This problem may be due to weakness in lower back muscles and ligament laxity which may be causing instability pain. There is a possibility of nerve root compression or inflammation which may be causing the problem.
Next Steps
I will suggest you to start with hot fomentation, use a lumbosacral belt for support, take analgesic with muscle relaxant tablet, apply analgesic ointment locally. Plan for getting MRI of lumbosacral spine if there is no relief..
Health Tips
Avoid heavy work, avoid forward bending, avoid sitting down, avoid Indian toilet, take complete bed rest.