Most of the times such pain is related to stress on spine.. which may be due to poor posture or related to work... Most of the times it is muscular pain... Especially at this age and when there are no symptoms in limbs...
Next Steps
avoid lifting weight or bending forwards
sit straight
in initial period cold compress the back and neck for 5 days or so
medicines for pain sos
Health Tips
still would be better if you can consult a neurosurgeon