I've had this random sharp stabbing pain in my left lung for about a year and a half now, it started after I had gotten the swine flu shot and mainly when I laughed. Now it happens at random and has started to affect my right lung and a few pains at where my heart would be. When I get this pain, I have to stop what I'm doing and I can't help my try and grab where the pain is even though it's internal. I'm 17 and I don't do any drugs and am not on any kind of medication. I asked a doctor to see if they could tell me what I was but they said they needed to know exactly the reason of why my pain starts. Is this anything serious because sometimes it gets worst and sometimes not. only happens about once every few days too.