Make sure under chats you have show notifications on
Also under chats if you click the word message notifications and group messages you should see a setting lock screen make sure it has show content picked.
It appears that facebook / whats app have disabled the option to get notifications - wish i knew this was going to be an issue as id have stuck with apple
Did you see the provided screenshots.
Can you send a screenshot of where your having an issue?
1.pull down notification panel
6. Turn on the setting show notifications
7. Message notifications click the word, then make sure lockscreen is marked show content
8. Repeat for group messages
Thank you for replies and screen shots, my settings were as you suggest except the group ones. My phone beeps and stays black, it doesnt light up and show you you have a message.