add action wp_head not working

Pull the add_action() outside of the function, and put the conditional inside the callback. Also, if you’re printing a script directly, use wp_print_scripts instead of wp_head. You also have a syntax error.

function testingone(){ 
    if( get_option( 'MyOptionName' ) ) {
        ?>
        <script>var Script = GoesHere; </script>
        <?php
    }
}
add_action( 'wp_print_scripts','testingone' );