What Causes Smelly Urine?

hi, i have suffered from a UTI in January and took antibiotics, wich cleared it up. In May i started to have very strong smelling urine, no discharge. Since then i have been back and forth to my Dr, i have had urine tests (all clear), swabs (all clear) and blood tests for Kidney, liver, thyroid function (all normal), now i have a sharp pain which comes and goes on my right side just above my hip, my stomach swells up all the time and then goes down. My bowel movements are normal. I am worried as this problem has persisted since January, and during the UTI i became very ill. Can you help? I'm 26 year old female, bmi of 22, healthy diet and no other medical conditions.