Using a loop to append query variables to a message - php

Question

I have an array of emails that I'm using to find paired their respective CourseID in a MySQL.
The loop should be finding each CourseID associated with that email and append it onto a message and then send it out when it's done. However, the email sends out the first $row['CourseID'] it finds and doesn't show the rest of the message or any other $row['CourseID'] that was found.
Here is my code, can anyone tell me what am I missing?
<?php
$courseList=array();
$studentList=array();
$subject="Course Surveys";
$con=mysqli_connect("","","","");
// Check connection
if (mysqli_connect_errno())
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
//populate the course list array
foreach ($_POST['queue'] as $cID)
{
array_push($courseList, $cID);
}
//find all the student emails in each course and put them into an array
for ($i=0; $i<=count($courseList);$i++)
{
$theCourse=$courseList[$i];
$foundemails=mysqli_query($con,"SELECT StudentEmail FROM Students WHERE CourseID='$theCourse'");
while($row=mysqli_fetch_array($foundemails)){
array_push($studentList, $row['StudentEmail']);
}
}
//strip email array of duplicates & restructure array
$studentList = array_unique($studentList);
$studentList = array_values($studentList);
//Send emails
for ($i=0;$i<=count($studentList);$i++)
{
$message = "Hello ".$studentList[$i].", please take the time to complete the following surveys:\n";
$result=mysqli_query($con,"SELECT * FROM Students WHERE StudentEmail='$studentList[$i]'"); /* USE ORDER BY StudentEmail */
while($row=mysqli_fetch_array($result)){
$hashed=md5($studentList[$i].$row['CourseID']);
$message .= $row['CourseID'].":\n http://khaledkloub.com/projects/admin/survey.php?id=".$hashed."\n";
}
mail($studentList[$i], $subject, $message, "From: Course Survey Manager\n");
}
mysqli_close($con);
?>

Answer 1

$message .= $row['CourseID']."\n";
OR
$message = $message . $row['CourseID']."\n";