welcome to HCM
You seem to be having recurrent UTI with back pain
. I would suggest you to get Urine analysis and culture done . the culture reports take 24-48hrs to come. Till then you can visit your physician and get further course of antibiotic . Nitrofurantoin
may be helpful.
Plenty of water helps in decreasing the infection.
may be needed to rule out if there is pyelonephritis
or any structural abnormality of the urinary system
.. But i don't understand the need for MRI.
UTI should not be a cause of worry but proper tretment is needed to avoid complications
Wish you good health.