Hi, many thanks for the query!
Yes, it is possible to have minimum pain, because pain is due to excessive contractions of ureteric smooth muscles to get rid of the stone, but your medicines like anti-spasmodics reduce these contractions & relieve pain.
Remember this is temporary & you can get another attack of
severe pain, also this is not the permanent treatment, 15 mm stone is very unlikely to pass out with just medicines, you should get operated for removal of the stone, otherwise back pressure changes caused by obstruction (by stone) in the form of
Hydronephrosis & Hydroureter will lead to compromise of
kidney function.
You should do- Sr.
creatinine, Sr. Uric acid, Urine (R&M).
Take antispasmodics, pain killers, diuretics with your doctor's opinion.
Wish you a good health.
Take care.
Regards.