It's the equivalent of a big sigh. He's just attention seeking....leave him alone for a bit and eventually he'll tell you what's the matter. My kids do it all the time.
Most people are not patient enough for this kind of game and this forum, peopled by bikers, is likely to be considerably less patient than average. For example, I felt irritated as soon as I didn't see what you're complaining about. You can tell Dr. Ruth :P