I am male 23.i feel like passing urine again and again at night. but i am perfectly healthy, my bloods tests and ct scan are perfectly fine . one doctor told me that may be i have weak bladder, he asked me to do kegel exercises? does it help?

Normal blood test means you do not have nocturia (voiding a lot at night) because of kidney disease. If weak bladder is the reason you should experience frequent voiding during the daytime as well. Do you drink a lot of water after dinner? How much volume have you voided each time? Any difficulty of voiding? Kegel exercise only helps with leaking the urine, not frequent voiding. See a urologist.