Yes, Chocolate does contain caffeine. I have a Mitral Valve Prolaspe and my Cardiologist informed me to stay a way from chocolate because of the caffeine; it can cause me to have palpitations.
I could, however, drink decaf coffee until IBS reared its ugly head. Of course, I had to give that up too. But as long as it helps my IBS, I really don't mind. And, when I gave up coffee, I had no withdrawal symptoms that I recognized. Perhaps the D and C was so bad I just did not notice.
Good Luck.
-------------------- God never promised life would be easy, but he did promise to provide a way out!