Weird Nexus S issue

I have my Nexus S updated to JB (4.1.1) and it has the strangest issue when making calls: I can't hear the person on the other side unless I set it to speaker phone. It isn't that the volume is too low either, the phone simply doesn't make any noise (including the dialing sounds) when I make a call. The phone has no issues when on speaker phone though, which is OK for when I'm in the car or at home but not preferable anywhere else.

Any and all help is welcome!

Please let me know if this isn't the kind of forum to be posting tech support Q's as well.