About a year and a half  or two years ago I noticed a bright red spot in the opening of my urethra. It's pretty small and only on the left side in a crease. Two years later and it's still there. I'm only 18 years old and it cannot be an STD as I noticed it before I ever had sex. Sometimes it burns when I urinate and stuff but not often. It's really starting to scare me and any ideas would be appreciated