I'm having an odd problem with my iphone 3g's volume button. I recently picked up my phone and saw that the volume screen would not disappear (volume was at max). Whenever I try to press the 'down' button, the volume would decrease by one bar but then increase instantly. Of course, these are all the symptoms of a stuck volume key ('up' key).
However, things get strange whenever I plug in headphones. The volume button works exactly as it should, both up and down, with no issues at all. Therefore, it can't be a hardware issue right? Once I plug in and unplug the headphones, everything is fine for an hour or so. Then the volume screen will pop up once again and the 'up' key will be "stuck."