Your analytics and reporting can be viewed directly in the Shopify app!
Here's how to do that.
1. Log into your Shopify account.
2. In the left hand column, click on Marketing (it has the bullhorn logo next to it)
3. Click on your Google Shopping campaign.
4. Click on the campaign again.
5. Under the header where it says 'Google Shopping Campaign,' click 'View Reports.'
This is where all of the analytics for your Google Shopping Campaign are housed!