Two doctors who once worked at a Pompano Beach pain clinic are among 11 people facing charges in connection with a three-year pill mill investigation headed by the Drug Enforcement Administration. Dr. Mark Cukierman, 56, was charged with racketeering and delivery of a controlled substance, among other charges. Dr. Michael Fronstin, 75, was arrested on charges of illegally prescribing a controlled substance by a practitioner and delivery of a controlled substance, according to a DEA spokesperson. The two are among seven doctors, three clinic owners and one of their relatives charged with racketeering and other criminal violations in South Florida. They all at one point or another worked at Pompano Beach Medical, formerly known as Pain Management Inc., said DEA spokeswoman Mia Ro.