As the pain is persistent over 4 months, you should get investigated for ruling out any bony cause for pain. Sometimes, there may occur sudden strain in lower back muscles which may also cause persistent pain.
Next Steps
Pls start with hot fomentation, take analgesic and muscle relaxant tablet as and when needed, apply analgesic ointment locally for pain relief.. Please get X ray of Lumbosacral spine AP and Lateral views
Health Tips
Avoid heavy work, avoid heavy exercises, avoid sitting down cross leg, avoid Indian toilet, avoid forward bending, avoid stair climbing..