As mentioned by you, that you are required to sit and work for hours long, i think the pain is due to mechanical load on your back and neck muscles.... when a muscle remains in the same position for a longer times, it tends to assume that position and ultimately leads to deviation in posture.... regular stretching of major back and neck muscles is required for you to get relief of the symptoms... take break every 30-40 minutes and do stretch for 4-5 minutes abd get back to work.... this should help you on longer run.... also seek an ergonomic advice for your workplace.... and yes, removing pillow is not a solution for your prob.
Using pillow is not the solution for your problem. You should consult ergonomist for your problem ad start streching and strengthening exercise for neck ad back. And best will be consult physiotherapist around your community .
Disclaimer : The content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding your medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.