I've had costochrondritis and it's very painful. Until I saw the doctor, it was in the back of my mind that I could be having a heart attack because it is chest pain, though my pain was centralized on my right side.
I had an x-ray to rule out a cracked/broken rib, and then I was diagnosed with costochrondrisis. The doctor gave me some pain pills, and eventually I felt better. The pain lasted for days, though. I wasn't able to lay down to sleep for several nights because getting into a sleep position hurt too much.
I hope I never get it again.