Welcome to Android Central! Try going to Settings>Apps, select Messaging, and Clear Cache. If that doesn't help, and you don't have any message threads you want to save, then Clear Data as well.
If that still doesn't work, then you could go to Settings>Apps, select Launcher (or whatever your phone's homescreen launcher is called--which phone do you have?) and Clear Cache/Clear Data. This will wipe the homescreens, so you'll have to set them back up again--so make a note of how it's set up right now.