$current_url="https://".$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI'];
	   header('Location: '.$current_url);

Here the complete code

<?php
	$postTitleError = '';
	$postcontentError = '';
	
	if ( isset( $_POST['submitted'] ) && isset( $_POST['post_nonce_field'] ) && wp_verify_nonce( $_POST['post_nonce_field'], 'post_nonce' ) ) {
	  if (trim($_POST['postTitle']) === '' || $_POST['postContent'] === '' ) {
	    if(trim($_POST['postTitle']) === '') {
	      $postTitleError = 'Please enter a title.';
	    }
	    if(trim($_POST['postContent']) === '') {
	      $postcontentError = 'Please enter a title.';
	    }
	  }
	  else {
	    $post_information = array(
	      'post_title' => esc_attr(strip_tags($_POST['postTitle'])),
	      'post_content' => esc_attr(strip_tags($_POST['postContent'])),
	      'post_status' => 'publish',           // Choose: publish, preview, future, pending, draft, etc.
	      'post_type' => 'post'
	    );
	    $post_id = wp_insert_post($post_information);

	    ?>
	    <?php
	  }
       $current_url="https://".$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI'];
	   header('Location: '.$current_url);
	  
	}
	

	?>

	<div class="col-xs-12">
	  <form action="" id="primaryPostForm" method="POST" enctype="multipart/form-data">
	    <div class="form-group">
	      <!--<label for="postTitle"><?php _e('Nome:', 'framework') ?></label>!-->
	      <input type="hidden" class="form-control" autocomplete="off" name="postTitle" id="postTitle" value="" placeholder="Nome:" required />
	    </div>
	    <?php if($postTitleError != '') { ?>
	      <span class="error"><?php echo $postTitleError; ?></span>
	      <div class="clearfix"></div>
	    <?php } ?>

	    <div class="form-group">
	      <!--<label for="postContent"><?php _e('Mensagem:', 'framework') ?></label>!-->
	      <textarea name="postContent" class="form-control" autocomplete="off" rows="4" placeholder="Mensagem..." ></textarea>
	    </div>
	    <?php if($postcontentError != '') { ?>
	      <span class="error"><?php echo $postcontentError; ?></span>
	      <div class="clearfix"></div>
	    <?php } ?>

	    <div class="form-group">
	      <?php wp_nonce_field('post_nonce', 'post_nonce_field'); ?>
	      <input type="hidden" name="submitted" id="submitted" value="true" />
	      <button type="submit" class="btn btn-primary btn-lg btn-block"><?php _e('Enviar', 'framework') ?></button>
	    </div>
	  </form>
	</div>

ERROR
Warning: Cannot modify header information – headers already sent by (output started at

tranks

It happened because anything echo or print before the header location call.
Currently i have modified the code please check it.

<?php
	$postTitleError = '';
	$postcontentError = '';
	
	
	if ( isset( $_POST['submitted'] ) && isset( $_POST['post_nonce_field'] ) && wp_verify_nonce( $_POST['post_nonce_field'], 'post_nonce' ) ) {
	
	  if (trim($_POST['postTitle']) === '' || $_POST['postContent'] === '' ) {
	    if(trim($_POST['postTitle']) === '') {
	      $postTitleError = 'Please enter a title.';
	    }
	    if(trim($_POST['postContent']) === '') {
	      $postcontentError = 'Please enter a title.';
	    }
	  }
	  else {
	    $post_information = array(
	      'post_title' => esc_attr(strip_tags($_POST['postTitle'])),
	      'post_content' => esc_attr(strip_tags($_POST['postContent'])),
	      'post_status' => 'publish',           // Choose: publish, preview, future, pending, draft, etc.
	      'post_type' => 'post'
	    );
	    $post_id = wp_insert_post($post_information);

	    ?>
	    <?php
	  }
					   $current_url="https://".$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI'];
						  if(!headers_sent())
						     {
								   header('Location: '.$current_url);
								   exit;
						    }
						else
						    {
						?>
							<script language="javascript">
							window.location.href = "<?PHP echo $current_url;?>";
							</script>
						<?php
						}		
	  
	}
	

	?>

Regards
Sumith