Was there water damage? Was it dropped? Anything? If it's still under warranty I would take it by Verizon. They might hook you up with a new phone. If you didn't damage it and it just started doing it on it's own, I would revert to factory settings.
I have this problem too. It is some sort of software issue, in my opinion. Closing the text message program or typing something in another program will fix it. I haven't been able to figure out the cause.