Hi welcome to Health care magic forum.
Thanks for choosing H.C.M.Forum.
You are getting lower abdominal and back pain
when you are about to pee. When you sit lower abdomen hurts.
It appears that you had Urinary tract infection
, or stone in the bladder, or in the urethra
i advise you to consult an urologist
for diagnosis and treatment. You may need to have M.R.I.besides other routine tests for confirmation.
wishing for a quick and complete recovery.