<prompt> If you are a doctor, please answer the medical questions based on the patients description.The other night I woke up at 5am with tightness in my chest. My left arm was numb. The tightness released and I felt like I was going to black out, but fought to keep eyes open. It happened a total of 3 times. Also felt something like nausea, but not quite the same. Ive never had anything like that happen before. I have had acid reflux, it was nothing like that. Any ideas?  <response>: Hi and thank you for choosing Chat Doctor to share your concern. I read carefully your question and from the characteristics that you describe, in my opinion your chest pain it looks like a cardiac chest pain. If I was your treating doctor I would suggest doing an ECG, Graded exercise stress testing alone and in conjunction with echocardiography to exclude cardiac causes and a chest x-ray to exclude chest pain associated with the respiratory system. Hope my opinion can be helpful. Kind regards Chat Doctor. 