iPhone 4 sporadically freezing when opening text and ipod.

I can't tell you how many times recently I have gone to send a text or open the ipod and it will either freeze or go to the apple sign and it seems like it goes back to the screen but keeps re-freezing until I have to restart it.

My software is up to date and I have had the phone since the first day with no problems. Does this sound familiar to anyone?
Thanks for any help!
Stephanie