Hi welcome to Health care magic forum.
Thanks for calling, H.C.M.Forum.
You had a stitch like feeling in the left side of stomach, lower back, slightly tender.
It appears to be the small stone in the urinary tract
, pobably at the end of uriter so causing pain in the back .
Other causes are hernia
of a small portion of the gut or mysentry. You may need to have M.R.I. for confirmation.
I suggest you to consult a surgeon for diagnosis and treatment. and to avoid strangulation of hernia.
Wishing for a quick and complete recovery.