Family History Of Prostate Cancer, Ovarian Cancer, Lung Cancer, Skin Cancer. Chances Of Developing Cancer?

Hi, I m worried about my risk of getting cancer and keep asking my doctors do to general physicals for me but they won t unless i have a specific problem. I was wondering how I could get them to do an mri scan or something of that type for me as I get very nervous thinking about the risk of me getting cancer. Both my grandfathers died of prostate cancer , my grandmother on my father s side died of ovarian cancer , my grandmother on my mothers side died of lung cancer , my father currently has prostate cancer and my aunt recently developed skin cancer. Kind of explains why I m so wary about my chances of getting it. My doctors know this information but they always just say don t worry about it which doesnt sound very assuring.