I would make each selection by the user a value entered into a related record. If you have a check box formatted field and the user selects 2 check boxes, that would be 2 related records thus created. This makes summing values from different sets of related records very easy as well as making how you structure this set of diagnostic questions and answers very flexible.
Note that you can use portals and buttons to script what looks and acts like a single field with checkboxes or radio buttons, but which actually uses scripted buttons and a related table to record the data.
Se the check boxes with scroll bars examples--especially example #2, for working examples of this method:
Thank you Phil!! - I will have to study the link and your answer, but thanks for starting me in the right direction. May have a followup in a day or two.