Unfortunately, the default price fields (machine-name commerce_price) on product types cannot be changed via the user interface. In Drupal 7, you can lock fields to prevent them from being deleted, which was essential to the product data model in Drupal Commerce. However, locking them also prevents the widget settings from being changed - including the label and description. I opened a bug report a while ago to address some of the deficiencies in the locking system, but it's still open.
At this point, your only recourse is to use Drupal's hook_form_alter() to alter the product form and make the desired changes to the label / description. If you just need to alter the default product edit form, its form ID is commerce_product_ui_product_form. However, if you're using the Inline Entity Form (as in Kickstart 2.x), you'll end up having to modify the node edit form itself, which will be a little more complex.