My mom suffers from intense lower abdominal pain, like strong urges to hold urine for a few minutes,

My mom suffers from intense lower abdominal pain, like strong urges to hold urine for a few minutes, or from sitting for long periods, or from bearing down or doing physical activities. When she goes to a medical center, they tell her that her bladder is contracted and that there is no urinary infection. I would like to know if she has interstitial cystitis or another condition, and what you would recommend to relieve her pain.