What you are describing could be anxiety disorder , please get evaluated . It is quite common to confuse anxiety symptoms with heart issues .. and often once tests results come normal , anxiety disorder is considered .
You will require anti-anxiety medicine , SSRI & other anxiolytics . Also if there are any stress / issues in life you can start counseling sessions .
Please consult a Psychiatrist and Don't delay treatment because it sometimes can become worse and then treatment required is more prolonged .
Hope this helps .
Next Steps
consult with Psychiatrist.
Health Tips
Apart from that , you need to start relaxation techniques such as box breathing , progressive muscle relaxation etc ..