OK. LIke everyone here I had sound issues this morning.
1. I have the Iphone 4s.
2. I have had it for a bout 2 years now.
3. I installed some new apps in the past few days.
4. This morning, no music from anything except that phone could ring.
5. Tried resetting - No Good.
This is what I did, not sure which one worked for me but, it is worth a try for you guys:
I deleted the three recently downloaded apps.
I updated all apps. from the App. Store.
I started to clean connector with Rubbing Alcohol and Amazingly I got some intermittent sounds.
I then stuck my charging cable in side the port, and pulled it in and out a few times, hopefully to clean it more.
The sound was still intermittent, and the song would pause whenever I moved the phone.
I went to Settings, Music, and turned "shake to shuffle" ON, it worked better but not perfect.
I then turned "shake to shuffle Off", and Turned "Sound Check" ON.
and this did it for me, my sound is back to normal. I can even turn "Sound Check" Off, and still have music.
I hope this helps someone. If you have any questions, let me know I will try to help.