Hi giana48,
We understand that when you are playing a song in Apple Music that a different song plays instead of the one you selected. Have you restarted your device to see if that helps? Are you updated to the newest software?
We'd like to have you go through the steps in the article below that could help with what you're experiencing with the Music app. Even though the title of this article is not what you are experiencing, the steps within could help.
If an app on your iPhone or iPad stops responding, closes unexpectedly, or won’t open
Also, can you tell us if this is happening when connected to Wi-Fi or cellular data?
Let us know.