Your Lumbar spine curvature is lost which is the cause of your back pain. It can be probably due to bad posture. So u need posture correction combined with Back extensor exercises. For pain relief u can do hot fomentation with towel soaked in lukewarm water for 30 minutes to back followed by application of Voveran Gel and a pain killer pills
Next Steps
Consult a Physiotherapist for back extensor exercises and more treatment options
Health Tips
Avoid forward bending, Lifting heavy weights and sitting in bad posture.