Thanks for your question on Healthcare Magic.
I can understand your concern.
No need to worry for heart diseases as your 2d echo and TMT (trade mill test) are normal.
In my opinion, you are mostly having musculoskeletal cause for your
chest discomfort.
Your chest discomfort is associated with exertion (playing tennis), so musculoskeletal cause is more likely.
So follow these steps for better symptomatic relief in musculoskeletal discomfort.
1. Avoid awkward movements.
2. Sit with proper back and chest support.
3. Apply warm water pad on affected areas of chest.
4. Avoid heavyweight lifting and strenuous exercise.
5. Avoid bad postures in sleep.
Don't worry, you will be alright with all these.
Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks.