From the description it seems that you are duplicating content controls to repeat values throughout the document. That being the case, why don't you use mapped controls to repeat the data? Then whatever is entered in one of them is repeated in the others so that the need to lock and unlock and thus the need for a macro seems moot.
https://www.gmayor.com/insert_content_control_addin.htm makes it even simpler to insert mapped content controls. Insert the first one then copy and paste it to the other locations.