Dejan you already made a post on this and I made a big response, why'd you start a new one? Anyways, I'll recap.
Tendinitus means that your tendons have been inflamed and became irritated. That results in a burning sensation. If you do not heed this warning sign and continue abusing your tendons, they can scar.
CTS is where the carpal tunnel (the "tunnel" in your wrist that the tendons go through has become inflamed, if persisted, scared. The scarring means that it swells and begins to pinch against the tendons, squeezing them, meaning that the warning sign of advanced CTS is a "tingling" in the fingers, and obviously the inability to do certain things like play guitar, use a keyboard, or any number of things depending on the severity.
I've had tendonitus, which I got by doing three straining activities at once (as in, in a day). Lifting weights, classical guitar (brutal on the right hand), and some intensive electric guitar. The first thing the psysiotherapist said to me, "Stop lifting weights! It's horrible on your wrists". So I did. I went about a week without any playing and then a week or two after of less playing, maybe half an hour to an hour a day. But it cleared up fine after that.
CTS is more serious, and isn't known to just "go away". It could involve invasive surgery which you DON'T want. My friend's dad had it, because he was a plumber and a guitarist (all those wrenches and things are bad on the wrists) and he still says he can't play the same after the surgery. That was over a decade ago.
So take this as a word of warning: be vigilant about your wrists! Be sure to warm up good before doing anything strenuous. Lots of hand excercises and nice and simple playing before you get intensive. Playing for long periods of time can also be dangerous, but of course I can't judge how much YOU can play at a time without being in danger; you know your body and it's capibilities, I don't.
Hope I didn't scare you TOO much :) Just remember to be vigilant, and if you get some mild tendonitus, its not a huge deal if you stop immediately. It just means a break for a bit. Be vigilant!