Last April while studying abroad in Hungary, I began having pain in my chest, mainly on my left side, and my left lower ribcage. While I though it was related to mild asthma, it got worse and I was sent to the ER. They diagnosed me with pericarditis. The pain lessened a bit, and when I got home in June I went to see a family doctor. He informed me that I had been misdiagnosed, and that I had costochondritis. He had me take naproxen for the pain. For a while it lessened, but it never fully went away. I've been off the naproxen for a few months, and the pain is now coming back, but only on my left side, below my rib cage on my left side. Is this still costochondritis? I'm worried that I've been misdiagnosed yet again. The only other symptom I've had is being very tired the last week or so. Any ideas?