I am having very dark brown odorless and pain-free discharge and I am %100 positive it is coming from my urethra. I had a pap smear less than a week ago and all results came back normal and all STD testing results came back negative. I also had a urine sample taken and I am not positive for everything they tested for but nothing turned up. The discharge began the day after I received my pap smear results. What could this be?