You need to check your sleeping position, pillow height/ firmness, and your sleeping mattress, if any recent changes are done or if its getting too old. Either of them might be at fault. Do some research ti correct it or a physio can help.
Apart from that, your work pattern, whether sedentary or active, sitting posture at your desk, work ergonomics need to be checked. Again a physio can help you here.
Next Steps
Start doing some neck, upper back and shoulder stretches throughout the day (youtube will help) and more importantly it should be the first thing after getting up in tbe morning. Take a hot water shower to warm yourself up, it helps.
Health Tips
*Rule out any deficiencies (vit D3,
calcium, vit
B12) and get proper treatment for that, if any.