Thansks or replying to the qestions..
I think ur problem is posture related..Improving ur posture especiaaly during working hour will help u a lot.U should sit erect with both the shoulder retracted backwards. Hsve a proper backrest, Forearm support.the moniter screen should be at the eye level.Remember to avoid sustained position,take exercise breaks,relax yourself and strenghten ur upper back muscles,core stabilisers of back aswell.