Spotify automatically playing music on Iphone despite the app being closed

[girlelectric]

For the last month or so, my iPhone will automatically open spotify and plays songs and even more annoyingly, whilst I´m listening to music in the gym or wherever, the Spotify app will just automatically skip songs and it is massively annoying! Even if I close the app, Spotify will play and then I have to open the app to stop the song. 

I´m not sure if this is a hardware issue or spotify issue. I´ve switched off Siri so it cant be this. Is anyone else having the same issue or have managed to fix this issue? It is driving me insane to say the least!