background music wont play on my iPhone 7

I got my (new iPhone 7 a couple months back, and was very dissapointed when I found out it wouldn’t play music in the background, but I assumed it was something the model didn’t offer. I recently found out my friend, with the same phone as me, can do this. When I’m on YouTube using Safari, I can’t press home without the music stopping. On my old iPhone it would pause but all I would have to do is press play and it would resume.