Allowing users to chosse only one option - Radio button

I would like to create a check box form tool and have two boxes that they can either check yes or no... so essentially adding another column of boxes 

Instead of using check boxes, I would suggest you to use radio buttons. Radio buttons allow user to chose only one option while with check boxes users can select multiple options. 

When you add radio button field to your form. click on Options and change default options to Yes and No.

However if you want to use Check Boxes with values Yes and No you can set Maximum Selection to 1.

Here is my demo form: http://form.jotformpro.com/form/51876672361968? 

Hope this will help. Let us know if you need further assistance.