Three years ago on New Years day, I drove myself to the ER, and walked in complaining of chest pains.
DAYUM, I got fast service!

They kept me over night, repeating blood tests every four hours, but finding no evidence of myocardial infarction. By noon the next morning, they figured out it was only pericarditis, i.e. inflammation of the tissue that encapsulates the heart, separating it from the lungs. The treatment was simply to start with a 4 x dosage of ibuprofen, then taper off to zero over a week. 20 minutes after the first dose, i was fine.

After a week, it was gone, and I've never had it again.