Burning and pain in urethra. Please sir.

Hello Doctor, Since last 1 month, i am having mild burning pain while urination and after urination also. Also slight pain and discomfort in urethra. Also it feels like bladder is not emptying fully after urination and also always feels like urination but small amount of urination happens. After urination, 2 to 3 drops urine dribble out once i seat on my chair immediately. I have done reports like Routine urine, Urine culture, Diabetes, Chlamydia IG, Gonorea , HIV, VDRL, KFT, LFT test, and CBC. All reports are normal. No UTI or no STI as per my Doctor. Normal KUB USG. My doctor has given me Cefpodoxime Proxetil (200mg) + Clavulanic Acid (125mg) for 10 days. Slight improvement but after finishing if the medication, pain comes again. I am in too much stress and tension since last 1 month. Request to help and advise please sir.