Q: Messages show up on my mac but not my iPhone 5s - Help??

I've recently bought a macbook pro and I linked it up with my iMessages from my iPhone 5s and everything was working til now.

For the past week maybe 2 weeks my messages have been playing up. I'll send an iMessage from my phone and then ill go off the app then back on again and it doesn't show up. Or ill send it and the app shuts down and when i go back on it its not there.

But if i look on my mac the messages are there. I also sometimes don't receive any messages on my phone either but they're on my mac.

Sometimes when i get a message i don't get a notification. Theres no sound, no banner or no red circle on the app.

I message my friend from both my mac and my phone and when i was on her chat on my phone kept making a noise as if i was getting new texts from her but i wasn't and it kept making the noise over and over again until i went off the app.

Ive tried resetting my phone, turning it off and on, turning iMessage off then on again, linking and unlinking iMessage to my mac. I don't know what else to do.

Please help me its driving me insane! Im worried someones going to urgently need me and i wont get their texts.

I know this was long but please help.

Thank you.