Coffee and Caffeine FAQ

I have been drinking iced tea.. very strong, iced tea every day for a long time.. years. I'm also a coke drinker, but last week I decided to stop doing caffeine all together.. I was having trouble staying asleep.. falling asleep was easy, staying asleep was a big problem. I've gotten a grip on the headaches, they're under control, but I've noticed the past couple days that all of my muscles, neck, legs, back, hips, even stomach muscles, everything has become so stiff. Also I've been a bit constipated.. I have always had regular bowel movements, no stress.. so I don't know. Could the lack of caffeine and maybe sugar cause any of these things to occur? I've been drinking nothing but water since I stopped caffeine, just trying to flush my system clean.. so any ideas?