I had protected sex about 6 weeks ago. About a week after I started to have tingling, itching and discharge at the tip of my penis. I went in about 2 weeks after the incident and had a STD test that came up negative for everything. The doctor said that I have a yeast infection. Now it is 6 weeks latter and I still have pain at the tip with a little swilling inside the urethra. Could the test have been wrong. Is this part of having a yeast infection or do I have something else?