text messages always contain music ... how to stop the music

"Text messages always contain music" - Not sure what you mean by that statement. Does that mean every time you get a text message you hear music? If YES then you may have some part of a music attached as a text tone. To double check and change the text tone-

Open Settings ➔ Sounds & Haptics ➔ Text Tone - Change the sound associated to the texts. Choose from the top portion of the available list of sounds.

Axel F.