Hello, your symptoms are probably caused by a lower urinary tract infection (LUTI) (cystitis). The back pain is not common though and sometimes urinary tract obstruction may mimic the symptoms of LUTI, particularly if the obstruction - a stone most of the times - has been stuck right before the entrance of the bladder. If the pain comes and goes then an obstruction has to be ruled out with an ultrasound scan. Otherwise treating as a LUTI is indicated. Antibiotics are required for the treatment of LUTI. The choice of antibiotic depends on previous medical history and exposure to other antibiotics in the recent past (3-4 months). Common first line choices include the combination of amoxicillin-clavulanate or trimethoprim-sulfamethoxazole and a more potent choice is a quinolone like ciprofloxacin. Each choice has positive and negative aspects. You d better consult your doctor for the proper regimen for you. Medication for the pain can be taken as needed. Prefer paracetamol and avoid non-steroidal anti-inflammatory drugs. For LUTI phenazopyridine provides some relief. I hope you find my comments helpful! You can contact me again, if you d like any clarification or further information. Kind Regards!