I had the same issue with my shopify and paypal account after switching email/paypal account to a newly created paypal account. I followed the suggestion provided above but couldn’t add additional email address on my new paypal account, at the same time, I realized that the email address on my new paypal account was not verified, so I verified the email address on my new paypal account and the pending amount showed up to my new paypal account right away, and the order showed as “Paid” on shopify account too.
Hope this helps.