Could your chair be causing your back pain?
It is human nature to start to slouch no matter what posture you started in and no matter what chair you use. A stability ball to tone your core, as often purported, would only engage those muscles for a few moments if you are sitting correctly. After that short time, it would do more damage than good due to the inevitable change in posture. You see, as homo sapiens we tend to move into a forward head posture, which causes a domino effect to our shoulder placement, then abdominal and pelvic stability, and lastly to our feet.
The solution: Use a timer. Whether you are sitting on a stability ball or not. If on a chair ball, set it for 4 minutes while practicing good posture then switch to a different chair. If on a regular chair, put your back against the back rest or (if the seat is too long or if your knees come up to the seat edge) a firm pillow and the back rest. Also practice keeping your ears over your shoulders, your elbows bent at 90 degrees and below your shoulders, and your knees and hips 90 degrees with feet flat on the floor. Again, the magic solution is the timer set for re-occuring 10 minutes to remind you to stretch, move your joints, and re-position in your chair while you continue your project.
There is much more info on neck placement, monitor height, wrist protection, and the actually stretches to do. Stay tuned for videos, links, and ways to improve your energy level with efficient posture and breath.