>>218what type of specialist?
there is a few possibilities, prinzmetal angina comes to mind, alternatively, conduction rhythm abnormalities may be possible (look up wolf parkinson white syndrome).
it would be wise to go for a checkup with your gp so he can refer you to get an ecg done (EKG if you are murrican) with adminsitration of a provocative agent.
usually prinzmetal angina dosent show anything on an ECG unless it is during an attack, so there is a possibility that it was for this reason it wasnt picked up by the specialist.
how often does this occur? if its more than once a day, 24 hour holter monitoring can be considered as a diagnostic tool.
alternatively, it could just be something like regular gastrosephageal reflux. (theres a name, i forget).
does anything make it better? does anything make it worse? e.g. like lying down
Are the attacks getting more frequent? if not, odds are you have nothing to worry about (although you should try to exercise a bit). if they are getting more frequent, best to go back to your gp and see him again.