Mail / Messages Non-Responsive

[DEFAULTx]

I'm not sure what triggers this but I've been having problems with my TP. All of a sudden, I won't be able to reply or forward my Messages but I can delete them. When I go to my Mail, I can only see the last email received as well as Picture Mail, but I can't go into the actual message to view it. I've tried everything to try & see if it's triggered somehow & I'm left with having to turn the phone off & on to get it working again. The phone is completely functional & I continue to receive Mail & Messages. Is anyone else having this issue?!