Severe Left Side And Back Pain Sent Me To ER,

Severe left side and back pain sent me to ER, had CT which showed 11 mm kidney stone in left kidney. Urologist sent me for xRay prior to lithotripsy, which did not show the stone. He concluded that it's probably a Uric acid stone and I should take baking soda to try to dissolve it and have another CT in 2 months. Yesterday I had the same kind of pain on the other side. Is it possible I have stone in right kidney as well? Do CT scans and xRays often miss kidney stones? Is baking soda really going to dissolve these if they are Uric acid stones?