Default [Q] G900F - Random Freezing, Phone won't wake up/ Help!

Hi Guys,

I have a rooted Samsung Galaxy S5 (G900F), and pretty much since day one had random freezing ie. unable to wake phone from standby.
The alert light still flashes as if the phone is on, but the phone does not wake.
Putting the phone into recovery sometimes is achievable, otherwise I take the battery out, ( I reboot, clearing cache etc on a daily basis.)
However, I get still get this problem.... I am not sure if this related to kitkat 4.4.2, or whether 4.4.3 will fix this.

I am using Omega ROM 5.0 (4.4.2)
Used titanium backup for restore.

I have tried the phone without the backup. and I still get this problem.

Any ideas, thanks in advance!
If this is a duplicate, please let me know which thread I should look at. I have read a few with no success.

Cheers,
Dave