As you have mentioned in your question that your work profile is such that you have to sit erect in front of system over a period of time .If your chair is comfortable make sure for your PC 's arrangement, as it should be in a same line to your shoulders of distance is not proper it may causes load to your shoulders and ultimately to your spine and causes back pain
and neck pain
.I suggest you to do some back strengthening exercises as well as neck strengthening exercises, and try to lean some self stretching exercises so that you can do them in between your free time
Continuous one steady posture
causes abnormalities and pain
so change position after an hour And pain is unbearable then you can use back belt or cervical collar for better support and precaution Thank you.