Hello Doctor, I am a 28 year old man and I

Patient: Hello Doctor,I am a 28 year old man and I feel I am suffering from a UTI. I have burning sensation while urinate since 7-8 weeks. It was very intermittent earlier. Since past 1 week I feel it almost always. I also noticed that there is a dar red (maroonish) spot on the tip of my penis near the opening.I also suffer from recurrent kidney stones and a stone around 7 mm had come out around 12 weeks back.I visited a GP and tests revealed I have multiple renal calculi in both kidneys. However, the urine test didnt show any presence of bacteria. The GP still prescribed me Cital syrup to ease my burning sensation and it did provide me relief but the pain returned soon after stopping the syrup. I visited a Nephrologist and he ruled out too possibility of UTI based on the symptoms and urine report. However my condition has worsened over time. I feel doctors are mixing up a UTI/STD with stone pain. Since I have had stones in past too, I can make out the difference with the way I feel pain. I am pretty sure this burning sensation is due to some infection. May be a UTI or STI.I am a shy person and was hesitant to see a urologist and get my private parts examined. I read a lot about my condition online and I suspect it is Urethritis that I have. I have started taking Cital syrup and Doxycycline since past 3 days bbut unfortunately doesnt seem to be helping much. May be I am not taking right medication? Or it takes longer to show effect?Does the general urine test detect the UTI bacteria? May be I need a urine test again to determine exact cause. But since I have been taking antibiotics, how long do I have to wait before taking test? I dont want the bacteria to be untraced in the test which probably happened last time.I am really depressed with my condition and shy to visit urologist too. Please advise.Thank you very much.

Symptoms: Burning sensation while urination, dark spot on tip of penis