@Jamie21: Please head to the Messages app > Tap the 3 dots in the top right > Settings > Notifications > On > General Notifications > Alert (tap to enable) > Sound > Select your preferred option. Go back and apply the same settings to 'New Messages', then close the Messages app and go to Settings > Sounds and Vibration, and make sure that Sound mode is enabled. Let me know if this helps.
I tried this but there is no general settings for my phone. Do you have another step by step? I have tried everything I can think of
Sorry I meant General Notofications