I don’t know of an easy way to get a side by side comparison of section heads for parallel passages.
You could use the Section Headings checklist (Tools > Checklists > Section Headings) to see just your section heads, but they are listed in the order they occur. If you have another project or resource with good section heads, you could choose it as a comparison text to compare side by side the section heads in your project with the section heads in the comparison text.
You could have this checklist open, and also open the Parallel passages tool to see which passages to compare the headings for, but you’d have to scroll manually up and down the list of section heads to find the parallel ones.