The investigations like EKG and calcium CT score are good for coronary artery disease. There is a disease called as arrhythmia, which need to be ruled out by the following tests;
1) Stress echocardiography
2) 48 hours or more of Holter monitoring.
I know you are young and this is the reason I specifically mentioned about the esophageal spams and acid reflux for your symptoms.
But an high index of suspicion need to be kept for your symptoms.
I would consider following also for your symptoms;
1) Esophageal spasm
2) Esophageal motility disorder
Following treatment may help you;
a) Calcium channel blockers (diltiazem, nifedipine) decreases the spasm and improves the movements of the esophagus.
b) Relaxation techniques.
c) Noncardiac chest pain in the setting of esophageal spasm and esophageal movement disorder (dysmotility) often shows good response to antireflux therapy, even in the absence of typical gastroesophageal reflux symptoms.
d) Reassurance and control of anxiety is extremely important if you have any.
Please feel free for your follow up questions.
I would be happy to assist you further, if you need any more information.
Thanks for using Just Answer.