Help No notification of multiple texts in conversation

[racinjunkie]

I do not receive any notification (audible or icon) of a new text when I'm in a conversation with someone. If I receive a text and respond to it and then hit to lock button I'm not notified of any new texts from the person I responded to. So, I have to keep the conversation open and watch the screen or I have no way of knowing the person has responded.

Help!