As per description of the issue, your morning stiffness may be because of muscular weakness. This can be due to forward bending activities of spine or by prolonged sitting hours.
Next Steps
To reduce this you can do stretching, isometric as well as strengthening exercises such as bridges.
Health Tips
Before starting any exercise program please do have a complete assessment by a physiotherapist.
Also try to avoid prolonged sitting.
Do not maintain same posture for more than 20-30min and take rest in between.
For further Consultation, you can contact again.