urologists - pain in urinary bladder during urine pass
Do you mean pain while passing urine?
The most common cause of pain while passing urine is infection. At times inflammation (cystitis) can also cause pain and so does structural abnormalities. A stone in the urinary tract cause pain in the lower abdomen while its passing through ureter; but not in the bladder.
To identify the real cause, you need to undergo a urine test - routine as well as culture and also have an ultrasound scan done
In the meantime, drink lots of water. Pain killers may be used for symptomatic relief. Specific treatment is based on test results.
Hope this helps. Let me know if you need clarifications.