If you need a flight physical near Naperville, this page lists 8 offices that came up in local searches for aviation medical examiners. The list is ranked by Google ratings, review volume, aviation focus, and search visibility. It is a starting point, not a final answer.
Only an FAA-designated Aviation Medical Examiner can issue an FAA medical certificate. Before you book, call the office and confirm they hold a current FAA designation and handle the class you need. Fees are set by each office, so ask about the price when you call. You can also check the FAA Designee Locator to confirm a designee.