[AndrewG]

If you think you have problems, pity the poor drummer who not only has to coordinate four limbs, all doing something different, but sings as well! That chap in the Eagles, Mr. Henley, comes to mind. It's like separating mind from body; knowing the guitar part so intuitively that muscle memory takes over so that you're almost playing on auto-pilot, leaving you to concentrate on the vocal part without having to think about what your hands are doing. It will come with time.