Legal Question in Medical Malpractice in California

The doctor doesn't have to treat you, unless you're brought to the ER and the doctor works there. The slavory is over. So, no the doctor doesn't have to treat every person who walks into his office.

As for being tested against your will, you have the right to refuse the test. No one can force you, except if there is a court order.

Your pain doctor is not a government employee, so forget about the 4th amendment. He is a private businessperson and he has the right to refuse service to anyone except for illegal reasons such as racial or ethnic discrimination. We get it that you benefit from smoking medical cannabis. The doctor probably perfoms "drug tests" to cover himself from legal malpractice liability, and to detect people who use narcotic drugs other than what he prescribes. He may also, rightly, fear being hassled by the drug enforcement authorities who have, rightly or wrongly, hassled or arrested many pain management doctors. Best guess he does not care all that much about cannabis. The best way to find out is to ask him. Be sure to tell him you do not want your discussion about cannabis charted in your medical records. Maybe you will find your fears are unfounded. Maybe not. If not you could ask for a referral to a pain doc who allows patients to also use medical cannabis. Best of luck.

"is it legal for a pain management doctor to deny me medical care when I refuse to take a drug test?"

YES, for the last time. YES.

There are only so many ways of saying it, trying to get you to understand. You have no 'right' or 'entitlement' to his services except on his terms. Just like any other business, he can refuse service to whomever he pleases, for whatever reason he pleases, including you having a bad or demanding attitude toward him, or refusing his requirements and requests. The customer is NOT always right, or to be obeyed.