Another thing that I take, that really works to help get rid of muscle stiffness after workouts is a good high dosage chelated Magnesium supplement. Preferably in a powder form mixed in water soon after your work out is best. If you do a search, you'll soon find a brand that suits you. Feel free to PM me if you want more info on what I use. Magnesium is a natural and powerful muscle relaxer. I got onto this about 3 months ago after experiencing the same upper body stiffness you describe. Its made a huge difference to my recovery time, not to mention vastly reduced muscle pain. And, if you need a natural anti-inflamatory, do some research on the "Boswelia" herb. Again another really powerful natural pain management compound.