Radiating pain right below the sternum. What could it be?

Four times now I have gotten a sharp radiating pain right below the sternum. Three of those times I've woken up to the pain and the other I was eating dinner. It hurts breathe and not to breathe. I haven't been able to find any position to sit or lay in to make the pain lessen. The pain is so overwhelming that I always vomit which helps at first, but the pain always comes back within 10 minutes. They seem to be getting more frequent and it is making me seriously worried. The last 2 attacks have been less than a month apart. Since I don't have medical insurance or a job atm I can't go to a doctor. Please someone at least tell me what it is or what I can take to make the pain go away or more bearable.