Speaking to your regular physician should not be an uncomfortable situation. After all it is your dime, and if your physician is still uncomfortable about the dialogue, remind him that your health trumps their comfort level.
Not all physicians feel cool prescribing marijuana, do not know about cannabis, or may be barred discussing at all because of hospital or medical network restrictions. There are several doctors who specialize in medical marijuana and can prescribe your marijuana, however, the conversation begins with your primary physician. And if you do not see a doctor, unfortunately the direction of medical marijuana legally begins with a licensed physician prescription. Sound familiar?
Personally, I would fire any primary doctor that could/would not prescribe cannabis to me. Unless I did not need it and was in excellent health 🙂