The IRS website will advise of any delays or holds on your return.  The quickest way to check the status of a tax refund is to go to "Where’s My Refund?" or call 800-829-1954 for automated phone service.

If you are chosen for a review you will be notified by the IRS (via mail) and the Wheres my refund tracker will be updated to reflect that as well. 

Due to the PATH Act and numerous recent changes in tax law,  2017 tax year returns are simply being processed a bit slower than years past.