Protected Sheet Will Not Allow Macro To Run

I have protected several sheets in my workbook to protect the forumlas and data for being tempered with by the users.

When I try to run my macro, I get an error message stating:

Runtime '1004'
You can not use this command on a protected sheet

And the debug is pointing to this part of my code

Do Until pr > .Cells(1, 1).SpecialCells(xlLastCell).Row

How can I revise my code to allow me to have my sheets stay protected and still be able to run my macro?