I have a pair of Nike Zoom Air II that's fairly new (sole not worn yet, maybe 20-30 hours of play), and the right heel started making this clicking sound when I walk, on every step, around the heel area. There's no visible crack or damage on the sole at all. The inside looks fine, too. Has anyone experience something similar on their shoes? Maybe the glue is undone a little bit somewhere? The shoe still seems to hold up fine. It's just annoying to have a little clicking sound when you walk around.