HI!

Yes, pls. check Page Sidebar setting in product options. 

We can give you a php code to enable sidebar on all products pages but you will can't disable it.

Do you need left or right sidebar?

You need to install child theme, copy woocommerce.php template from parent TheGem theme to child and in this template in child after code:

    $thegem_sidebar_stiky = $thegem_item_data['sidebar_sticky'] ? 1 : 0;
    $thegem_sidebar_position = thegem_check_array_value(array('', 'left', 'right'), $thegem_item_data['sidebar_position'], '');

    if(is_product()) {
        $thegem_sidebar_position = 'left';
    }