burning sensation inside tip of penis

                   sir,before 6 months i have 20-30 blood drops come after passing urine .that time doctor give me cital syrup and  nitrofurantoin  while detecting uti (sensation while passing urine).At that time  problem sorted out in 15-20 days.now from  one month ago  same  problem   raised but now i feel all time sensation in tip of penis , taking same medicine and had done test-ultra sound-usg kub,hiv,hbs ag,vdrl,cbc,urine re & me,urine      c/s,urea l na/to sotaat say(urine for culture,fungal,afb),-----all result normal.What test should done to find problem? or what may be my problem?