Yesterday afternoon I experienced some weird chest pains. It was right under the area where my heart is--felt like I was being stabbed by something. Whenever it would throb more my knee would ache A LOT. It went away after about...30 minutes or so. I looked up the symptoms on webmd.com and it says I need to see a doctor, but it didn't tell me what was exactly wrong. Does anyone have any idea what's exactly wrong?