Burning Sensation In Penis And Anus, Uti And Sti Tests Clear. Advice Required?

Hi Doctor I ve been having burning or stinging in my penis and my anus area ever since i had protected oral sex with a girl a few times over 12 months ago, the pee hole seems to get red and sore sometimes and my fore skin has been reddess as if it has a rash and like little white pimples underneath the outside of the foreskin , Doctor said that the thing on the foreskin is no harm. I have been to my doctor a few times and had uti , sti tests done but all clear, the doctor also gave me antibiotics for the burning and cream for the foreskin problem. The girl i was with also fingered my anus as well as the oral sex. I found the oral hurt at times and am wondering did i get injured. Its really starting to bug me. Sometimes the pain and stinging seems to disappear for days but then returns, i ve been drinking lots of water and cranberry juice although i do notice alcohol seems to make it worse and i get a soreness at the bottom of my stomach sometimes. Really hope you can help me or give me some advice. Regards Ben