Hello and thankyou for approaching DoctorSpring with your query.
I have gone through your case and understand your concern.
Since you have got yourself tested for any heart problem and all your tests have come out fine , you have nothing to worry.
If you have done the following tests 1) ECG 2) Cardiac Biomarkers 3) ECHO and they have come normal, it rules out any heart cause of your pain.

In that case your symptoms of pain, numbness and breathing fast are most likely due to stress or anxiety related.
Have you been anxious and low lately or stressed lately?
Do you feel dull or feeling of no energy as you go through your day?
Do you feel irritated or angry easily?
If you do have the above symptoms, it is likely your stress is anxiety related and will subside. You will have to find ways to deal with your stress like yoga, exercise, or outdoor activities. If the have been feeling low, stressed anxious or depressed for a prolonged period of time, say around 3-6 months or longer, I would advise you to visit a psychiatrist and have a counselling session.

Since your cardiac(heart) tests have come normal you have nothing to worry.

I hope this has helped. Feel free to follow up.
Thankyou