worried about MRI and CT scan of head

[g_caine02]

For 5 months now I've had problems with numbness in my fingers, stiffness in my neck, swollen lymph nodes on the back of my neck and a lump just below my earlobe on the right side of my neck that i am told is a knot of muscle. I had trouble sleeping so i recorded myslef with a digital camera and found that i do some sort of single convulse or heavy twitch that wakes me up. I took all of these problems to the doctor who had many tests done as well as refering me to an ENT. nothing to do with my neck showed any problems so the ENT refered me to and ear and eye institute where i was told no signs of problems yet again. In that referral process i got my hands on the results of the CT scan and MRI i had done.  There is an anomaly about 20-30 mm in diameter and spherical in shape just to the right side of my cerebellum that does not show up on the left side at all. it shows up in the contrast MRI as a white mass. Completely black in the non contrast. It also shows up as white outlined grey mass on the CT. it shows up on several "slices" of both tests. I pointed it out to my PCP who called the radiologist  and quickly dismissed it as normal blood flow on the MRI and as cerebellum tissue on the CT! His responses have left me very far from confident in his deductions. I'm at a loss. Can i force my PCP to refer me to a Neurolgist? Is there anyone qualified to tell me what that mass is for sure? some one please help the symptoms are taking control of my daily life