New messages not showing on screen

I recently purchased an Apple Watch and in the past week, when a text, What's App or email arrive I get the notification on my watch but not on my phone. The screen no longer lights up to show the message. If I pick my phone up, then I can see it but it does not send an alert. I've checked DND is switched off and compared with my families phones to see if I have anything different but it is all the same. Any ideas? I know I get the notification on my watch but I don't always notice that and I'm missing messages on my phone. Thanks.