Thanks for your question on Health Care Magic.
I can understand your concern.
Since your ecg is normal, no need to worry much for cardiac diseases.
But better to get done stress test
. It will tell you about your heart function in stress like exercise.
If this is also normal than you are mostly having stress and anxiety
So better to consult psychiatrist
and get done counseling sessions.
Try to identify stressor in your life and start working on its solution.
You may need anxiolytic drugs too.
So avoid stress and tension. Be relax and calm.
Don't worry, you will be alright. First get done stress test.
Hope I have solved your query.
Wish you good health. Thanks.