I am working as computer engg. Job need eight hour seating daily. I have noticed recently I can not  seat straight for more than five minutes. I feel pain in my back  and feel discomfort if I tried to seat with back straight without any support , always need to  lean back to pillow or some support. Even on chair or sofa I lean back on upper body and neck. I tried to correct posture few days but pain in back makes it impossible for me. Should I consultant doctor if yes which type of doctor I should consult.