Retrieving Checkbox Values from Plugin
You can pull an array of all the options for a checkbox field by calling getOptions():

$options = $entry-&gt;storyCategories-&gt;getOptions();


Each option will be an object with three properties, label, value and selected. To get all selected options for a field, you can loop through the options and test for the selected property:

$options = $entry-&gt;storyCategories-&gt;getOptions();
$selectedOptions = array();
foreach ( $options as $option ) {
    if ( $option-&gt;selected ) {
        $selectedOptions[] = $option;
    }
}


Note that this exact code will work for Dropdown, Multi-select and Radio button fields as well.