I’m trying to sub-divide a questionnaire that I am using a SharePoint List for into sections and have done so by entering the Section Name as a question. I am now trying to change the font of the section names so they stand out more and remove the text field that is opposite the section name.
Since you mentioned you're using a SharePoint list, I'm going to make the assumption you are talking about a Custom List. You can use Sharepoint Designer to copy the existing NewForm.aspx page then modify as you need to to create the desired look.
Close/hide the existing web part on the page and add in a new Custom List form. This will output all the columns in your custom list. You can then alter the markup however you see fit. You can create sections and modify CSS without having to use questions as section breaks.