How to change "Shop" title on all individual product pages?

Are you talking about the breadcrumb trail? If so check out the link:
https://gist.github.com/jameskoster/5849055

Or are you talking about the title of the Shop page? Can change title via Appearance > Menus > Click on Home drop down arrow & change Title in the Navigation Label.

Hope this helps

This is the template you are looking for https://github.com/woothemes/woocommerce/blob/master/templates/single-product/title.php