Hi there grace28!
Oh dear, I'm so very sorry to learn that accessing your messages has been a real hassle since the update. Good thing your friendly local VZW agent is here to fix everything. So, let's delve right in.
The one thing I've noticed to help immensely with an issue like this is clearing out some data. Simply go to settings > applications > manage applications > all > find the messaging app > clear data > force close. Then go ahead and restart your device to start fresh and attempt to access your messaging applications. I hope this helps and if not, please feel free to reach back out.
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