Anal Warts question

Years ago i noticed a tiny bump on the shaft of my penis. I guess i got it from having unprotected sex. I am a straight male, never had anal sex. I got it removed, and it never came back. The doc told me that this isn't cancerous. I kept getting checked up and he said that there was no more warts. A few months later my anus became very very itchy at night. I tried to check and i felt bumps in there. I was sure they were hemmeroids. Some doctors said hemmeroids, one of them told me it was warts. I was scheduled to get them removed but i heard the recovery process was long and painfully so i put it off. The warts have seemed to go away, but my anus is still very very very itchy. Is this normal? Also am i not at risk for anal cancer if the ones on my shaft werent cancerous? I dont understand, if the visibile ones arent canceroues how are people getting anal cancer? Please help, thanks you.