I would suggest a complete physical by your doctor and a qualified Physical Therapist to review your posture, sitting arrangement at work and also find a qualified person to make sure your work area is conducive to your situation
I would then talk to your boss about taking a stretch/move break every 30 minutes for 2 minutes.
You may also consider hiring a Certified Qualified Personal trainer that can assist you with a workout program
Also: I realize you work long hours, however, consider getting up a bit earlier in your day and going for a walk for at least 20 minutes if possible, then another 20 in the evening!
Personally, I don’t recommend creams.