Most common reason for this kind of back pain is usually
vitamin B12 and D3 deficiency. I recommend that you get these tested in any nearby good lab. It's a simple blood test. The pain subsides once these vitamins are started.
Next Steps
For immediate pain relief you apply hot bag followed by any pain relieving gel. I hope this helps.
Health Tips
If the pain persists even after taking painkillers, you need to visit a nearby Orthopedics doctor.