Sounds strange. You can always try to clear data for the messaging application which can be found under Settings > Apps > The tab "All" > Messaging > Clear data.
But if the problem persist, I suggest that you delete your messages to see if this can help. You can make a backup on your text
messages via the pre-installed "Backup & Restore" app if you would like to save them but I would recommend you to wait to restore this data after deleting the text messages.
