Painful and burning urination

Patient: What could be the problem? Why do I have burning and painful urination?I have no Kidney stone or gallbladder stone. Nothing on my Urine test. Ultrasound says my right kidney’s size’s 63*32 mm and my left’s 104*54mm. I’m asking you this because my doctor says I need to have some sort of test which involves radioactive stuff and it might be a little dangerous.

Symptoms: Burning and painful urination. There’s no blood. After urination all parts of Urine tract system feels kind of a warm with a slight pain.