I am not a fan of Apple, and just started using it with iPhone 6S for office purposes. I was having the same issue. Here's what I did: Firstly, closed all the running apps from the background by double tapping the home button and then swiping up. Secondaly, opened Safari, and closed all the running Tabs, and then closed Safari by following the step 1 again. Last and final step, opened the Music app, and fully closed it again. And that's all. The Music Widget is now magically gone from my lockscreen. I hope that it works for other people too!