Ringer not working with incoming calls, sound not working on games

Hi, my phone isn't ringing when I get calls. The sounds for games are also not working. Sounds are turned on in settings. The sounds work when I change the volume, etc. in the settings panel. The ringer is not turned off...checked that. Sound on movies and music is working. What magic switch am I missing?! This has not been a problem before. I starting using the alarm on the phone last week, but I don't think there's a correlation since I turned off the alarm to test and still didn't have any ringtone with an incoming call. Thank you.