How do I add space to my Bootcamp partition? I'm starting to program and use both Mac and Windows. I need to add space to my Windows Bootcamp partition, so I went into Disk Utility and shrank my Mac volume. But now my Bootcamp partition doesn't appear when restarting holding Option. I also can't create an image of my Windows partition using Disk Utility in Mac, says I don't have permission.

I read that you could just split the Mac partition, reboot into Windows and use Minitool Partition Wizard to add the split space into Bootcamp. How can I get this to work? Thank you for any help.
You could try this : with Disk Utility, restore you Mac volume to its original size (no free space left between the Mac volume and the Windows partition), then launch Boot Camp assistant from Mac OS (in /Applications/Utilities), and use the Boot Camp assistant for redistributing free space between Mac OS and Windows partitions.