Crazy question, and totally not insulting your intelligence, but you don't have airplane mode on without realizing it, right? (It's happened...)
I'd make a full backup and then flash the stock rom...then flash aokp again. Then restore your apps only (no data) using Titanium. Basically start from scratch without really starting from scratch. Crazy things happen flashing and reflashing....data can clash with other old data etc etc.
What messaging app are you using? Have you changed any settings in any scripts at all? I'd also check once I flashed the stock ROM that none of the settings in the phones ##3282# menu aren't totally jacked. Have you flashed a firmware/radio zip and accidently powered off the phone in the process? Crazier things have happened.
Those are a few ideas that come to mind....it's also 3am and I'm beat lol. Hopefully that helps - let me know and I'll try and help ya.