Böyle bir şey yazdım incelerseniz sevinirim.
<fieldset><label>Dersi Veren Hoca</label>
<?php
$katQuery = query("SELECT * FROM courses ORDER BY course_id ASC");
while($katRow = row($katQuery)){
echo '<input type="checkbox" ';
echo $katRow["course_id"] == $row["course_name"] ? 'selected ' : null;
echo 'value="'.$katRow["course_id"].'">'.ss($katRow["course_name"])." ".ss($katRow["lecturer_surname"]).'</input>';
}
?>
</fieldset>