problem with apple headphones?

In december I got a new iPod touch. In the box it came in there was the charger, and also a pair of apple headphones. These headphones are brand new and have never been used, but the plug on them doesn't fit into the jack on my iPod. The plug doesn't fit into the jack on my macbook pro either. I have checked, and there doesn't appear to be any blockages in either of the jacks. On the iPod it goes maybe 70% in, and on the macbook 90%. What could the problem be?