How to Block Share on Facebook
Facebook gives you the necessary privacy controls to adjust sharing on your profile. You can limit how people tag you in photos and videos, stipulate how people comment or share your posts and restrict the ability to share content or make posts to your Facebook wall. Additionally, you can prevent people from revealing your location through Facebook Places, which is especially important when you don't want all your friends knowing where you are. The Facebook Places feature lets you or your friends check in at different locations and share where you are with the convenience of a mobile phone.
Sign in to your Facebook account, go to the "Account" menu and select "Privacy Settings."
Go to the "Sharing on Facebook" section and click the "Customize Settings" link near the bottom.
Go to the "Things Others Share" section and edit the settings you want to change.
Click the "Edit Settings" button for "Photos and videos you're tagged in" if you want to restrict who can see the photos and videos you are in.
Click the check box for "Friends can post on my Wall" to deselect the item. When you do this, then your friends cannot post or share items to your Facebook wall.
Click "Edit Settings" for the "Friends can check me in to Places" option. On the next screen, select the "Enabled" button and switch it to "Disabled." Click the "Okay" button when done. Now your friends cannot share your location.