Talk to Urologist on Urinary Retention

My urine went block and I got cyctitis. Emergrency dr put the catheder to release urine and my ultrasound report shows I got cystitis. Dr told me that it had occured due to UTI, so first I was prescribed Ciprofloxacin two times daily for 5 days but symptoms did not get better. After that, I was prescribed Furolin 100 mg 4 times daily for 12 days then my urine started releasing again but my post void urine volume was 66ml. After finishing the course of medicines, my urine has almost blocked again. What is the possible cause of my urinary retention?

Please note: urine dr, urine culture, creatinine, cbc, LFT all are normal. New ultrasound scan shows no sign of cyctitis but post void volume was 66ml.

Please suggest what I can do to get rid of this.

All the problems started related to my urinary after the second dose of Moderna(Covid vaccine)