Running a macro and trying to lock cells that get moved?

Prefacing with: I don’t know anything; everything I’ve done so far has been pilfered through Google searches.

I have a worksheet that has a column with a bunch of values, and a sum of those values at the bottom of the column. The macro I’ve built copies and inserts that column next to the existing one when the user presses a button if they need another column. It references the column header and selects the paste location based off of the column title.

I’ve been asked to lock the sum cell in each column but am really struggling with how to lock a cell whose reference would constantly be changing. Eg, my worksheet would have A16 and B16 already existing and needing to be protected. Then I’d run the macro and need A16, B16 and C16 protected. Hitting the button again, now D16 would also need to be protected. Can I somehow assign this as a variable?

I vaguely understand the sheet needs to start off protected, be unprotected, and then re-protected at the end of the macro but that’s as far as I’ve gotten.

Any help is extremely appreciated!!

EDIT: I am so sorry. The copy / paste function also copies the cell's locked formatting, so I have imagined my own problem. If I just un protect and reprotect, the new cells that have been pasted are locked.