First off - deep breaths. You said yourself that more than likely what you're feeling is linked to sleep deprivation. I'd suggest you actually let your body rest. You might also want to stay away from caffeine for a bit considering that makes the heart race. If you feel as though there's more to this, I suggest speaking to a cardiologist.
Hello! I am a 19 year old male who suffers from random chest pains. It first happened last November and I too had ECG tests and blood tests and they came out fine. I went to the hospital specifically one time because my left arm was feeling tingly so I thought I was suffering from a heart attack.
From my experience, I believe it is just your anxiety. I now know that most of the pain and stuff was from anxiety as soon as my blood tests and ECG and x-ray came out fine.
You will be ok. What really helped me calm down was getting into a comfortable position (sitting, lying down, whatever it may be), play a peaceful, anxiety-relieving song off of youtube, close my eyes, and take deep breaths and focus on nothing but that. Doing that just for 5 minutes helped out a lot.
Best wishes to you!