Apple iPhone is a great piece of technology and like any other gadget can be the source of little annoyances which are simple but tricky to solve, one such commonly encountered problem is when your iPhone thinks it's always connected to a dock and no sound comes out of the device speakers as it diverts all audio to the phantom Dock Connector. Once stuck into the "Dock Connector" mode the volume slider becomes nonoperational and no audio comes out from internal speakers with no option to change the behavior and route audio to internal speakers.

Try the following to fix the no sound from iPhone problem, you should check whether sound is working or not after every step :

1. Plug and unplug your iPhone dock connector to try and fix the wrong stucked connected status for the dock.
2. Plug and unplug your iPhone charger cable (strange but it did worked for me at times).
3. Plug and unplug headphone into the provided 3.5 mm jack.
4. Try blowing warm air into the connector dock.
5. This problem is most probably because of some sorted pin in the iPhone cable connector socket, take a dry brush/toothbrush/canvas-paint brush and gently clean any lint in there.
6. If anyone of the above does not work take a needle and clean the docking connector with it, this is what worked for me - the connector had almost 1mm think layer of dirt accumulation which needed careful cleaning using the needle. Be careful with this and advised this could permanently damage the connector, you can also use alcohol as an cleaning agent with this.
7. If everything fails it's time to get the connector pin replaced.