Q: Why am i constantly having to "add this(my) computer" to iTunes match?

Hello DSpurling71,

If you're being prompted to authorize your computer every time you launch iTunes, which may result in the interruption of matching your iTunes Library's contents, the steps detailed in the article linked below can help get things stabilized.

If iTunes repeatedly prompts you to authorize your computer
https://support.apple.com/en-us/HT203160

Sincerely