B/C I know that I'll get "go to the dr. you moron" responses, I will first say that I am going to go this evening - that said, I blv I know what is causing this and wanted some feedback. I was at mile 5 on my way to 15 yesterday when suddenly I got pain/strange sensation in center of chest/lungs area. I immediately stopped and took pulse which was 150, so normal for my effort. I'm 36 and training for Richmond Marathon on Nov 12. I don't have a fever or any other symptoms. My bp is 115/75, cholestoral low etc.My pulse returned to normal, but the pain did not subside. It is now the following day and I have discomfort when I twist in certain ways and when I breathe deeply. The pain is in the center of the chest and goes straight thru to the center of the back in about a "quarter-sized" feeling if that makes sense. I think I strained a muscle and want to keep running (marathon 2 weeks away) but wanted to see if anyone has had similar experience. I've read webmd on angina, pleurisy, blot clot in lung etc. But, I really think it's a muscle strain or stitch. Any thoughts?