Since when you are having this problem? Is it sudden or it was gradual.? Is it radiating to legs.?
For pain relief use ice pack or hot bag 10 min-15min three times a day.
Or you can use pain'relieving gel or ointment like volini gel or spray.
Start doing exercises for back like back strengthening exercises, core strengthening, side stretch,.knee isometric as well. Quadriceps stretch. Try to do heel standing,toe standing.to increase blood flow and release tightness.
Next Steps
Avoid forward bending,no long sitting , always use pillow under your back. try to take small break inbetween your work.
avoid lifting heavy weight.
Health Tips
To get proper treatment use practo app and physiotherapists consultation . do exercises regularly.