I know it's frustrating when the tests haven't shown anything.
Sometimes when a person is observing himself, reads info on some
diseases and is worried to get the symptoms, this stress may
develop such symptoms. Then it's a psychical problem.
Anyway, to find out if you have any heart problems or not, I
suggest you ask for the Holter's heart monitor, it's a portable
monitor of the size of a walkman which monitors your heart
activity, ECG and blood pressure. You wear it for 24 hrs and do
your normal activities which you do in your life or by which you
feel the symptoms, it records the monitored data and then the
doctors transfer those data to a computer which analyzes them. If
there is something wrong, the doctor will see it. The only problem
is whether the doctor takes your complaining about the symptoms
seriously and agrees with the holter's monitor test.
Does anyone in your family (one of your parents, grandparents,
uncles, aunts and also in earlier age then usually) have the same
problems like you?