From what I've read,
The biopsy experience from patient to patient varies due to several factors. The number of cores taken, the striking of a nerve, resistance to Lidocaine or other numbing agents, improper application of numbing agents, prostate shape and size, and a prostate that is just sensitive to pain, all can factor into why one patient has pain issues and another does not. Saturation biopsies almost always require a general anesthesia because the prostate is hit from 24 to 45 times or more. It is recommended in these cases to be "put under" because they almost always cause sharp pain.
For me the experience was only uncomfortable, but only 8 core were taken. I don't know why standard biopsies are from 6 to 16 cores from doctor to doctor, only to say they do weigh the fact that the more minimizing pain with less intrusion versus knowing that more cores might be necessary to find cancer.
Also, if you tend to have fear that you will suffer pain, you can always tell your doctor you would like hin to put you under. This is your choice not his.
Tony