PHP- how to get values from checked checkboxes and corresponding textboxes

I want to get three values separated by a comma when the form is submitted. The value from the checkbox, textbox 1 and textbox 2.

This is my code that retrieves values from mysql database and generates checkboxes and two corresponding textboxes.

<?php

$query = "SELECT * FROM subject";
$data = mysqli_query($con, $query);

while ($row = mysqli_fetch_array($data)){
$s = $row['sub'];
echo $s;
?>

<input type="checkbox" name="req_sub[]" value= "<?php echo $s; ?>" />
<input type="text" name="<?php echo $s; ?>" placeholder="Total Number" />
<input type="text" name="<?php echo $s; ?>" placeholder="Pass Number" />     

<?php 
} 
?>
<input type="submit" name="submit" value="Add">

Suppose the user checks the first three boxes , and enters the values like in this picture -

when I click add, I get the values --
Physics
Math
Chemistry
by using the code below:

<?php
if(isset($_POST['submit'])) {
if(!empty($_POST['req_sub'])) {
foreach($_POST['req_sub'] as $selected) {

echo $selected."</br>";
     }
  }
}

but how do I get the values like this-
Physics,40,30
Math,40,30
Chemistry,30,25

I want this output in a variable so that I can store it in my database table.
I have spent several hours behind this in last few days. Please help me with this one.