I had that problem (text message not sending) after i installed the layars application. i rebooted my phone and it still had the text message problem. So i uninstalled the application and now i have no problems. Something in the application is getting access to my text message app and not allowing them to be sent out. This is a big bug in the LAYAR application.
My Photon crashed while sending a text last night (Handcent), and willnow no longer send any text - it is still recieving texts but nothing will go out - the little blue "wheel" spins but never completes sending the text.
Resets, half a dozen so far and two battery pulls have not helped.
Open to all ideas that do not include factory resets (last resort - too much does not get backed up - call logs and texts I have to have for billing purposes.)
I've had this text issue since I got the phone. Most of the time, texts go out fine, but occasionally it doesn't send. Not sure what is causing the issue and I don't have any of those apps mentioned above that are supposedly causing the problem. I never had this issue when I had my Samsung Epic.