ipad mini sound problem

Hello, my ipad mini that I bought a month ago was working fine when I first bought it. but now theres a problem with the sound. The thing is, at first i realised the game Sims sound was muted, although the volume is on, and then i figured the sound of messages, keyboard and mails etc was not working... i can listen to music and youtube works fine, today i realized that also at facebook app video sounds are muted. I beleive this is a operating system malfunction, what can i do to correct the problem... i am not sure but the problem may have started after the new ios update...