Q Every time I try to split the display in screen, it just freezes the session and the only way I have found to get around this problem is to shut the session down, which means I am unable to re-connect to the session. I am current running Fedora with Screen version 4.00.02.
A Screen's keybindings are case sensitive. The command to split a screen is Ctrl+a S, with a capital S. Ctrl+a s, with a lower-case s, sends a control-s (xoff) to the terminal. This is the command to stop any output. You can do the same in a normal terminal with Ctrl+s. Ctrl+s effectively freezes the terminal, which is exactly what you are seeing. Now that you know the difference it should not happen again, but if you do forget to press the Shift key, Ctrl+a q sends a control-q (xon) to resume the terminal's output. If you want to use the split function regularly, it may be better to bind it to an easier key combination. Add these lines to the file .screenrc in your home directory:
bind ^S xoff bind s split
Now 'Ctrl+a s' will split the screen and 'Ctrl+a Ctrl+s' will send an xoff to pause the terminal.