YouTube comment sections, notorious for some of the most foul language and abuse on the Internet, are nevertheless a useful way to connect with a content provider. While YouTube makes it easy for you to find comments that others have made on your own videos, YouTube no longer collects your own comments in one place for you, so finding the comments you've posted can be a bit tricky, but it is not impossible.
After you've signed into YouTube, click on History. Once on your History page, you can navigate to either your Watch history or your Search history.
Your YouTube Watch history is organized chronologically starting from the most recent post you have watched. To find your comments, scroll down through your history until you find the post with the comments you want.