I think there are two possiblties in you .
1. It can be cervical spondylitis
which is common in computer operators and whilte collar jobs. When we sit for long time in same position muscles get fatigue
.I think you have not done MRI of the neck. I would also suggest you to start neck
muscle strengthening exercises.
2. Other common cause of such pain can be trapezitis. If there is no sign of nerve
compression at MRi then a steroid
injection can help you.