What causes pain in the lower back?
Patient: The physician at Urgent Care thinks I passed a kidney stone on Friday of last week. Now my lower left back is aching. Am I likely to have another kidney stone or could this be a kidney infection? I can t get in to see a urologist until May 9th! Suggestions? Doctor: Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice.  What kind of pain is this? Is it severe pain that comes and goes? If yes pain is most likely due to renal stone passing through ureter like colicky pain. If pain is constant type that relieves on rest likely cause is mechanical back ache. I would like to advise X-ray of KUB  to check for the renal stone? If report shows stone you need to consult urologist. Kidney infection is less likely as fever will be there. If report is negative for stone pain may be originating from back. In that case visit to spine specialist will be needed. You van take tab Ultracet for pain relief.  Hope I have answered your query. Let me know if I can assist you further.