here were a few things in your "posted" code that were missing.
A missing semi-colon at the end of $message = "hello" (unless that was a typo/paste error?) and a dot in the first $headers
Also, not having a From: header attribute will surely result having the Email sent to and regarded as SPAM.
Having fixed those issues and added extra header information, the following code worked and did not end up in my SPAM, but the INBOX successfully.
<?php
$to = "xxxx@xxxx.com";
$email = "email@example.com";
$subject = 'xxxx';
$message = "hello";
$headers = 'MIME-Version: 1.0' . "\r\n";
$headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n";
$headers .= "From: $email" . "\r\n" .
"Reply-To: $email" . "\r\n" .
"X-Mailer: PHP/" . phpversion();
mail($to, $subject, $message, $headers);
?>
Or with a success echo'ed message:
<?php
$to = "xxxx@xxxx.com";
$email = "email@example.com";
$subject = 'xxxx';
$message = "hello";
$headers = 'MIME-Version: 1.0' . "\r\n";
$headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n";
$headers .= "From: $email" . "\r\n" .
"Reply-To: $email" . "\r\n" .
"X-Mailer: PHP/" . phpversion();
if(mail($to, $subject, $message, $headers))
{
echo "Message sent.";
}
else{
echo "Something went wrong.";
}
?>
Visit the PHP.net website for more information on the mail() and header() functions.

Social Plugin