Hi Sandhya...pain in the neck and going upto your back can be a sign of early cervical disc disease (especially if your daily routine includes use of mobile phones and laptops).
Next Steps
The best next step would be to go and see an orthopaedic surgeon. But in the meanwhile, you may apply a hot water bag over your neck (twice a day for 10 min), then apply any painkilling Gel.
Also, avoid using pillow while sleeping, keep mobile phone away from your body while looking at its screen and raise the level of your laptop screen so that it is at the same level as your eyes.