The following code shows how to put checkbox and label inside well.
<!DOCTYPE HTML>
<html>
<head>
<link rel="stylesheet"
href="https://maxcdn.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap.min.css">
</head><!-- w w w . j a v a 2 s . c om-->
<body style='margin: 20px;'>
<div class='container'>
<div class='row span12'>
<div class="well">
<input type='checkbox' id='three'> <label for='three'>Hello</label>
</div>
</div>
</div>
</body>
</html>