If I have recurrent urethral pain, should I repeat the sowing after discontinuation of the antibiotic, or ask my doctor again for metronidazole?

For three months I have had pains in the urethra and bladder, not only after the miction, and constantly. The sowing comes out sterilized, urine is cloudy, with the presence of blood, ketones and proteins, large amounts of mucus and epithelium, lack of leukocytes. Of the 15 drugs only 3 have brought me relief, Amoxicillin, Doxycillin and Metronidazole. With the fact that amoxicillin 2 tablets, doxycillin 10 days, 2 times a day, metronidazole 10 days to thevaginally 2x daily. After the end of the drugs, the problem returned, the coil hurts constantly, the bladder pulls. The PCR urogenitic panel came out negatively (after 12 drugs and 3 days after amoxicillin). Is it better to wait and do tests that will be more reliable than the ordered sowing during antibiotic therapy, or ask the doctor once again for Metronidazole for more than 10 days, when it helps, and as if it did not hit? Please reply, greet