i know the feeling. and it's horrible thinking "argh!! i've got this!!" or "oh no!! i'm probably going to die because of that being linked to that and possibly causing this that and the other!"
but, you can NEVER be too certain exactly what is causing certain things that you are scared of. not without hardcore probing (lol?). it's good to be aware of what your body is doing, and what you can do to help it keep in good condition. but you can only do so much. unless you really are ill and any pain is noticible beyond just "what was that?" it's more than likely nothing you need to worry about. everybody gets pains here there and everywhere. no matter how fit and healthy they are.
at least you know it's hyperchondria (cyberchondria). knowing that is, in its self, the first step to getting over the constant worry.