Chest pain that won't go away?

A month ago, I had very severe chest pain. It hurt to talk, breathe, function. The severe pain lasted for about a day until disappearing. I dismissed it as a small muscle pull or something, but the pain isn't going away. I'll feel dull pain in the area about once a day. But now the pain is returning more frequently and more painful. The pain is localized to one spot under my collar bone and above my right . The area is tender. Pain is okay for now, but the area, when not hurting, feels like "there's a hole" or something. What's up with this?