My sound I not working, how can I restore it?

All sounds? Or just alerts or music?

Is it the same with earbuds and without?

First take a look at this:

Understanding the side switch

http://support.apple.com/kb/HT4085

Then try this:

Make sure IOS is updated to latest version

(How to update your iOS device

http://support.apple.com/kb/HT4623)

Reboot device by pressing both the home button and sleep/wake (power) buttons at the same time for 10-15 seconds until the apple logo appears on the screen, then let go.

If that doesn't work then reset the device by going to settings/general/reset/reset all settings (or for network connection issues 'reset network settings').

(no media or data will be deleted from the device, this will only take a minute).