I have bought my Bose-in-ear headphone nearly three months ago and feel it has really been working with a very good sound quality. My colleagues admire I have this excellent headphone. So I am happy for owning it and everyday, I use it to listen my favorite music on my MP4. But about one month later, I feel a little pain in my ears when I use my Bose-in-ear headphone. Although I'm not sure what caused this, I feel it's related to my using method. Maybe I shouldn't use it so frequently and sliped it into my ears too deep. I feel the design of my Bose-in-ear headphone is up-to-date and humanizing....