43 male. experiencing pain in perineum and rectum only when sitting everyday for 2 months. goes away when standing. also urge to urinate same amount of time read these are major signs of prostate cancer. is this what i have. doctor says prostatitis?

In certain sitting positions e.g. riding a bike the prostatic area can get irritated and give symptoms like yours. It is not prostate cancer. Stop reading whatever source you read for it is scary garbage . Always ask your doc. It is not classic prostatitis with that you would not feel better when standing and you would have the symptoms all the time. modify your sitting position and use a cushion