Hello guys. I don't know what were happened on my iPhone now. My volume and my sound already on. Then when I received any massage or notification from any social networking my iPhone sound didn't work it. But when I got calling phone everything work it like a normal. Moreover when I want to play any video or want to play music, the sound still not work it. Sometimes all that will work it, but sometimes did not work it. So what should I do? And someone please let me know, why all that thing happens to my iPhone?