Recurrent Chest Sensation/Pain? I'm a 23 year old male, non smoker, fit and active, never used drugs and i have the occasioanal drink.

Since January of this year i've had chest pain that has come and gone. The first time i visted the ER and they did an ECG and everything came up fine and i went home. They felt it was anxiety and after that the pain went away for a few months.

It returned mid February and in that time i visited the ER 5 times and had an ECG each time that came up normal. I had an x-ray that showed my chest was normal.

My GP sent me to a cardiologist where i had an echocardiogram done that was normal and a stress test that was normal. My METS from the stress test was 16 and i reached 93% of the predicted age related maximal heart rate. Peak BPM was 184.

I have never experienced the pain while exercising. It is mostly at night but it does happen during the day. The sensation is almost like a pinch near my left breast.

I'm under no stress yet doctors feel it may be anxiety. I do not. Any ideas ?

Summarized question: What are possible causes of recurrent chest pain near the left breast mostly at night in young people?