Problem with getting speaker to work after using headphones

Have you tried turning up your volume? I asked that because that happened to me before. I thought that my iPhone had stopped working, but for some reason the internal speaker volume went very low. Another thing, How did you switch on and off your iPhone? Did you just turn it on/off in an usual way? Have you tried holding the power and home button at the same time for about 8 sec.? Perhaps, That method could resolve your issue.

Hi, I had this very annoying problem but know how to fix it now. At first, I thought something was very wrong with my phone. So I restored several times, called Apple, etc. with no success. What you have to do is play the volume trick just right. When your external speaker isn't working, plug your earphones back in. Then hold your volume up button. Continue to hold while you pull the earphones out, then release and turn your volume up a bit for good measure. This has worked every time since. Hope it helps! Welcome to the community, and enjoy your new 4s!