The US government does not interfere with the legitimate prescribing of medications for pain patients. The unscrupulous doctors that get kickbacks from those who sell prescription narcotics on the street, the doctors that are trafficing in drugs themselves, etc are those pursued by the government. Drug DIVERSION is the only area of interest the US government has in the prescribing of narcotics and as long as there is no diversion, the doctors and patients are safe. The amount of pills prescribed has nothing to do with diversion, therefore the government does not limit the amount. The usual course of business means the prescriptions are written in a legitimate medical office during usual office hours with appropriate documentation of the diagnosis and therapy, and are not being prescribed in the back of a parking lot infested with narcs.
Medicine is a business, just as is law, the church, education, or any other profession.