There is the stock text app, then there is also Chomp and Handcent. Does this occur with all 3 of them? If it happens frequently enough something may be wrong with whichever software you are using. It doesn't sound hardware related to me.
And..Welcome to the forum!
If you apply a rom or theme - backup first!
If you don't know how to backup...Stop until you do.
hint: I name my backups like this: sg6.0_20100428 or ss4.2_20100626 to easily find them later. rom and date.
Have a Problem, Click here to Visit the Rescue Squad
Levi, welcome. That sounds like software (just as cristim stated) You are using the "droid" right? Any way, try a hard reboot. Shut it off pull the battery for a few minutes then boot her back up, see what happens?
There are free SMS apps from the market!
-Respect is rule #1
-Email us at DroidForumPromo@gmail to become a Supporting Vendor.
-Not around as often as I used to be... Still, feel free to PM me if there is anything I can help with!