Have you done the following?
1) go to home screen while there, pull battery, SIM card, and SD card. Then while battery, SIM card, and SD card are out, hold the power button for about 10 seconds.
Put SIM card, SD card, and battery back in and power phone up.
2) delete all messages, and go into app manager. Under ALL find messaging app. Go into it and clear the data and clear the cache.
See if that works.