Could this chest pain be a cardiac condition?

I'm a 21 year old female, about a month and a half ago I started having this chest pain, still, today it's still there from a 1 to a 10 I would say it's around 8-10, the pain is mostly from the sternum to the left side and it radiates to the same spot on my back, the Dr. did an ECG which said "atrial flutter", "left side ischemia" and "ventricular strain", because of this they did an Echocardiogram and a 24 hr Holter, they saw that I didn't have arrhythmia, now the Dr. ordered a chest plate for SOB and chest pain and a stress test, the pain is almost unbearable, sometimes I get dizzy, and I'm getting this cough but there is no blood in it, at least he asked me that. I don't smoke, don't drink, don't take hormones, and I haven't done anything out of the ordinary like an excessive force, have or had an injury or a severe cough it just started one day... what could this really be, could it just be inflammation?