Thanks for your question on Health Care Magic.
By your history and description, possibility of
stress and
anxiety related symptoms is more.
Your symptoms are improving with Cardio workout. Heart and lung diseases actually precipitate after Cardio workout. So possibility of major heart and lung diseases is very less.
Stress and anxiety can cause similar symptoms.
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.
Don't worry, you will be alright.
Avoid stress and tension, be relax and calm.
Hope I have solved your query.
Wish you good health. Thanks.