What do episodes of severe chest pain mean?

Severe CP. Chest pain that is severe, lasting more than 30 min is considered an emergency needing you to seek immediate medical attention. It could be an heart attack, pulmonary embolism or aneurysm, all life threatening conditions which need to be ruled out before considering less severe causes.
Get help. The problem may be trivial or extremely serious, so finding the cause of the pain is critical. If you are having severe, or even mild chest pain, get it checked out at once.