Given your other posts- it appears you may need some assistance/treatment for substance abuse/misuse.
Taking more of a medication than you are prescribed is abuse/misuse. Obtaining Controlled substance prescriptions from two different drs is ILLEGAL and can result in not only being blacklisted in drs offices and pharmacies, but criminal charges for doctor shopping to obtain controlled substances.
It is also dangerous and can easily result in accidental overdose, respiratory suppression and death.
Many pharmacies use a controlled substances tracking system that shows when you last obtained opiates, benzodiazepines, when they were filled, the quantity , dosing schedule and name of the dr that wrote them. Pharmacists are under legal obligation to notify your drs if you try to obtain meds from different drs or too soon.
I would rethink your plan and seek substance misuse treatment.
No- it is illegal. Doctors in most states are required by law to check the drug database to ensure a patient is not obtaining prescriptions for controlled substances from multiple providers. Pharmacists must also check the database for last fill date, quantity, dosing instructions, and notify any prescribers that you attempted to fill another prescription from another physician. They may also be required to report to law enforcement.