ignorere header header("location") efter $_SESSION

Kode 

<?php
$username=($_POST['username']);
$password=(sha1($_POST['password']));
session_name();
session_start();
include("config.php");  
if (empty($_POST['username']) || empty($_POST['password'])) {
	header("location: login.php");
}
else {
$result = mysql_query("SELECT * FROM login WHERE username='$username'");
while($row = mysql_fetch_array($result))
  {		  
if ($password != $row['password']) {
session_unset();
session_destroy();
header("location: login.php");
}
elseif ($password == $row['password']) {
$_SESSION['run']='on';
header("location: upload.php");
}
};
};
?>