Looking on the internet deeply has found these results:

thanks for taking pain is the most popular phrase on the web.

thanks for taking pains 111,100 results on the web	thanks for taking pain 112,700 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:

thanks for taking pains

111,100 results on the web

thanks for taking pain

112,700 results on the web

More popular!