Postural low back ache due to constant working strain in office. You need to maintain erect posture while sitting, take mild analgesics and apply volitra gel and take hot water fomentation twice daily .Take rest whenever you find time
Next Steps
If not getting better after a week time then get good physiotherapy for a week to 10 days time
Health Tips
Avoid forward bending, weight lifting, sitting on the floor, stretching exercises for 2 weeks.