[NIKKG]

I get the problem too sometimes. The cause is overheating I believe. When your streaming lots of music or video, especially over the cell network, the phone gets real hot internally and for some reason its unable to switch to phone speaker when you unplug the headphones.

The only way for me to fully get it back working is to take out the battery for a minute to let the phone cool down. When I am streaming through wifi, it doesn’t do that since the wifi doesn’t heat up the phone as much as the cell network.