Q: Issues with 9.3.1 IOS

Greetings WasimSM,

Thanks for using the Apple Support Communities!

I understand that you are only able to hear sound from your iPhone when your EarPods are connected and the volume buttons do not appear to be working. To begin troubleshooting these situations, because they seem related, I would first suggest reading over and working through the suggested steps from the following article. 

If you hear no sound or distorted sound from your iPhone, iPad, or iPod touch speaker - Apple Support

Have a great day!