I have a sharp stabbing pain which seems to be stemming from beneath my clavicle on the left side, what should i do?

Wait before U worry: What you describe is not typical of any serious ailment unless it persists or gets worse. I would have you watch/monitor it for a couple of weeks in order to judge if it is anything significant. Most likely it will go away on its own. or you can take a couple of Tylenol tablets if the pain is causing you much discomfort. If the pain is still present in 3 weeks, get yourself checked by your PCP.