Hello and welcome to Apple Support Communities Tico18,
I see that you're having an issue with your Apple Watch pausing music when raising your wrist. I understand your concern, and I'd be happy to look into this with you.
First, let's have you restart your Apple Watch and then test to see if the issue remains.
Restart Apple Watch
If the issue remains, try turning off raise to wake while you're working out.
Turn on and wake Apple Watch
I also recommend reviewing the "A better fit means better readings" section of support article Wearing your Apple Watch for suggestions on wearing your Apple Watch.
Let me know how this goes.