Your general practitioner is far more qualified to answer this question than we are here. It seems he gave you a diagnosis, so that should be your foremost thought. Try not to be too anxious about it. (I know that's easier said than done.)
What we do know is that the chest pain that you describe can be caused by any number of things. If you had a cold, it could be congestion. If you had heartburn, it could be acid reflux. If the pain is relieved by movement, it could be anything from muscles to peptic conditions and gas. And, the list of possible causes is probably a mile long.
If the pain persists, I would return to the practitioner.