Stops playing if you do anything on your phone.

I have an iPhone 6S. For about 4 months now it has been getting worse and worse. If I open anything else on my phone the music stops playing. If I open the app itself the music stops playing. It behaves like a memory problem. Im about to go back to Spotify and cancel my google subscription. Its that bad..,almost complexly useless. FIX THIS

Aronhalt about Google Play Music, v3.35.1010