My form inside a modal is not working PHP HTML - php

Question

This is my code, I was supposed to get the inputted value in db and php tag isnt working.. It is not also redirecting to "myorders.php"; My form inside is not working.. Thank you.. Really need some help :(((
<div class="container">
<form method="post">
<h2>Enter your Pin Number</h2>
<!-- Trigger the modal with a button -->
<button type="button" class="btn btn-info btn-lg" data-toggle="modal" data-target="#myModal">Open Modal</button>
<!-- Modal -->
<div class="modal fade" id="myModal" role="dialog">
<div class="modal-dialog">
<!-- Modal content-->
<div class="modal-content">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal">×</button>
<h4 class="modal-title">Enter your Pin Number</h4>
</div>
<div class="modal-body text-center">
<input type="password" id="first-name" required="required" class="form-control" name="pin">
</div>
<div class="modal-footer">
<button type="submit" name="submit3" class="btn btn-default" data-dismiss="modal"><i class="fa fa-key"></i> Confirm Pin</button>
</div>
</div>
</div>
</div>
<!-- START OF PHP -->
<?php include ('connectdb.php');
if(isset($_POST['submit3']))
{
$pin = $_POST["pin"];
$pww = "123";
if ($pin!=$pww) {
echo "WRONG PIN.. TRY AGAIN..";
}
else{
header('Location: myorders.php');
}
} // SUBMIT
?>
</form>
</div>

Answer 1

As per my comment, remove data-dismiss="modal" from your submit button. data-dismiss="modal" is used to close the modal dialog. You already have it here
<button type="button" class="close" data-dismiss="modal">×</button>