I think you should get one MRI of Lumbosacral spine.
This problem may occur due to some nerve root compression at lumbar level.
Next Steps
Take complete bed rest for now. Start hot fomentation, take analgesic with muscle relaxant tablet,
calcium and
vitamin d supplement. Use Lumbosacral belt for support.
Health Tips
Avoid heavy work, avoid sitting down, avoid Indian toilet, avoid forward bending, avoid stair climbing and descending..