Occasional stabbing pain when breathing?

As long as I can remember, from time to time I will get, with no warning, a sharp, stabbing pain in my chest when breathing. I'll breathe in and suddenly its like someone has shoved a needle through my chest. It can happen on either side of my chest and its always in the same location on one side or the other, right at the base of the rib cage. When it happens, I can't breathe for a second or two, as breathing in causes the pain, but then it goes away.

This happens at random times, does not appear to be more frequent with exercise, and does not appear to be caused by any activity. It also leaves no lingering after effects, other than I feel a little hesitant to breathe for a few moments, wondering if it will come back.

Does anyone else experience this? I've mentioned it to doctors a few times, but none of them ever had an explanation. They just told me to tell them if it gets worse or chronic.