We'll create fresh WordPress site with Posts Social Shares Count installed. You have 20 minutes to test the plugin after that site we'll be deleted.
You can use this plugin to get the number of shares for a given post by ID.
To count for example how many times the post or page has been shared on Facebook use the function echo pssc_facebook() in the loop or echo pssc_facebook( $post_id ) anywhere. This function will return the count integer for example 5 or 0.
Or you can use the shortcode [pssc_facebook] in the post you want to count shares for or [pssc_facebook post_id=””] for a specific post by ID.
Note that PHP functions needs to be echoed.