A few months ago, I faced this problem and figured it out. I would like to share my experience so it might help you. See following steps to figure this issue.
Tag: google adsense
Google Adsense Tips: My Adsense Placement Experiments
If you are regular user of this blog, you notice that the theme and Google Adsense placement are changed many times. I have done many experiments related to Google Adsense placement. Here I am sharing information regarding the impact of Google Adsense ads position on different places.