Color changes and social media buttons

I am kind of a newbie to WP and have the most basic knowledge of html/css, just enough to get me by. I have a few questions on how to further customize my site. First, I would like to know how I can change the background color behind the blog posts, not the main background. Also, is it possible to change the white header background color as well? Or maybe even fill it up completely with an image so that there is no border? My other question was about the social media buttons. Is there a way to change their location to either one of my side menus or even on the top right side of the main header where the search bar option is?   Thanks for your help! And if it makes a difference, the site is www.pinmyselfskinny.com :)