Wierd pain above breast but below collar bone on the left side of my chest what could this be?:

This may be: from a pinched nerve in your neck at C6-7 level(s) (or the early signs of SHINGLES in that nerve) This can cause referred pain to your shoulder/upper chest! Check it out with your Primary Care Provider! Hope this helps! Dr Z

Hard to say: You will need to discuss chest pain (how long, how hard, how bad, how much worse) with a doctor. It is not going to be a heart attack since you are twenty. It is likely to be gone within hours, if not, seek medical attention.