Posture, arthritis, cervical spine issues, TOS, Reynauds, diabetes and other things can cause this to happen along with CRPS/RSD.

Try sitting up straight concentrate on your breathing and gently roll your shoulders by making circles with them, then follow that with a few shoulder shrugs (holding it in the shrug for a second or two) and then relaxing. This usually helps with cervical tension and helps blood circulate.

Check also that your keyboard, mouse, chair and monitor are at proper ergonomic height as this can play havoc on already weakened muscles and blood flow.

Tingly/numbness that is positional rather than constant makes me wonder if you do not have something going on in your spine? This can easily be overlooked by medical professionals especially after being diagnosed with RSD.