Medical cannabis and how to procure it

Hi! I'm a young woman about to undergo a major surgery for breast cancer. I was diagnosed in February of last year. I'm already experiencing a decreased quality of life due to my shoulder and neck pain presumably caused by the intense radiation I received. I know this will only get worse after my mastectomy.I take the THC edibles that I can get at a shop but I'm considering a medical card. I'm rather disappointed that my surgeon won't prescribe me some Ativan. Is it worth asking my oncologist about this or is there a specific doctor around that can certify me? I'm pretty upset and preparing to be pushed out the door with no anxiety medication and no pain meds other than Tylenol judging by this. So I don't know if it's worth pursuing this with them.