Using medi-cal, doctors lie to you?

ok my doctor gave me a hernia examination (i am using medi-cal)..she put me up for an ultra sound..and they gave me one..it lasted for a good 10 minutes...and they said everything is fine...do you think if they found something actually wrong that they wouldnt tell me? like for example if they found some form of testicular cancer in my testis that they wouldnt tell me because of my insurance??