How to add sidebar to single question page?

Please send me username & password of your site via private answer, I will help you resolve it.

I have helped you add the sidebar to your site, you can check your site now. If you want to change the widget in the sidebar, you can log into Dashboard > Appearance > widget.

Thanks, its all fixed now. 
I also added a tiny piece of html code on top of the single-question.php file so that the question title appears in header on top on single question page, is that safe?
Editing: dw-question-answer-pro/templates/single-question.php 

Yes, If you do not this custom will lose when updating the plugin, you can Go to your theme folder (wp-content/themes/[theme-name]), and create a new folder, named it “dwqa-templates”. Inside your new folder, copy the single-question.php file and paste into the dwqa-templates folder.