Hello,. I had gone through your question I can understand your concern. There are three important causes to the pain you have referred. One is sextually transmitting disease that you have ruled out. Second one is bacterial infection for which you have taken medication. Third one and most important is fungal infection, these are most common cause of burning sensation during urination and also cause redness or whiting of affected tissue. For that you must take anti fungal medication like fluconazole. Hope it will help you and you will write to us further, we will like to help you. Regards Dr Muzaffar