Thank you for your query at AskTheDoctor.com
I understand your concern.
You have pain in the lower back area on the right side and also on the right leg. The leg also cramps easily, and the pain is relieved on urination.
Since you have done ultrasound this rules out any kidney pathology, however, in some cases, ultrasound is inadequate and CT KUB is a better option. Infections such as cystitis are not picked up on ultrasound easily until and unless there is substantial damage from the infection.
Your symptoms are suggestive of urinary tract infection, mostly cystitis. In cystitis, there will be constant lower back pain and an urge to urinate, with a radiating pain in the lower limb. Cystitis can be extremely difficult to diagnose as culture reports can be unremarkable. I will advise you to consult your physician who can recommend a course of antibiotic for you. A good choice antibiotic for such infections would be Doxycycline with a recommended dosage of 100 mg twice daily for adults. This needs to be continued for 10-14 days depending on the severity of the infection. You can also request for a CT KUB. Keep drinking plenty of water as this helps in excreting the organism easily and does not let it lodge in the urinary tract preventing colonisation.
Hope this was helpful,
Feel free to discuss further,
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