Try sitting up with a correct posture (back straight, head and neck up) and try to take breaks and move around.
Good posture involves training your body to stand, walk, sit and lie in positions where the least strain is placed on supporting muscles and ligaments during movement or weight-bearing activities.
Push your hips as far back as they can go in the chair. Adjust the seat height so your feet are flat on the floor and your knees equal to, or slightly lower than, your hips. Adjust the back of the chair to a 100°-110° reclined angle.
