Yes....that is exactly what psychosamatic pain is. It happens to many many people with anxiety.
I have had the brain tumor anxiety myself. I had it bascially all summer last summer....I kept looking up the symptoms, and I kept feeling the symptoms. I was pretty convinced I had a brain tumor.
Well, I had this AND heart palpitations which culminated in me freaking out one day and going to the ER.
I had soooo many tests done, including a CT scan, and all came back normal.
You know what? My brain tumor symptoms went away the VERY NEXT DAY.
If I were you, and your doc knows you have anxiety, I would go to the doctor and tell her/him your brain tumor fears. They understand anxiety...they will assess your symptoms and let you know if they think there is any chance it IS a brain tumor. Brain tumors are rare, esp. if you are not middle aged or eldery.
In my opinion, there is no piont wasting time worrying needlessly if you can go to doc and have your worries alleviated.
Good luck, and I totally understand how you feel!