If you want to see how different your legs are, there are different ways that do not result in pain as you’ve discovered. The Functional Movement Screen (http://www.functionalmovement.com, see: http://www.functionalmovement.com/files/articles/116a_fms%20pb.pdf for a summary) has a good test called the inline lunge which can show imbalances between your two sides.  If you want to give it a try, the FMS Home Study manual is here: http://www.functionalmovement.com/content/Media/HSC.pdf.  The Hurdle Step test is another good one to try.