Can you legally be prescribed two narcotics at same time for two separate things?

If you are on a controlled substance, the law enforcement community has a record of every pill you are taking. If they see a new prescription they are going to investigate. They might do no more than convince one of the doctors to modify the prescription but action can and likely will be taken. Yes, it is Big Brother out there but that's the way life is these days; you can represent yourself in a murder case against you (without any legal training) but you have no rights to evaluate your health and self-prescribe medications for your ailments.

Doctors can prescribe what they want. Even deadly combinations have been prescribed by accident. So just because your doctor prescribed it doesn't mean it is safe.

It is the patients job to keep doctors update to date on their current medications.

The situation you are talking about is best handled by a pain clinic instead of two different doctors.

First off no narcotic prescription is for life any more. It is illegal for a doctor to write such a script.

It is up to you to notify your doctor what drugs other doctors have you on.

If you go to a different doctor, it is YOUR RESPONSIBILITY to inform that doctor of any medication you are currently on. It's very, very easy to overdose on pain killers, at the very least, liver damage from too much acetaminophen ("Tylenol"), which is very common in pain killers.

Legal, though of course the would have told the second doctor about the first prescription, and likely there would be no second one.

Why wouldn't it be? The doctors don't need permission to prescribe drugs.