I Have Problem In Emptying My Urinary Bladder Totally, And

I have problem in emptying my urinary bladder totally, and always have to shake my penis after urinating for a long time but still when I move a step I feel there is some urine in my penis then I have to urinate again. Please help me , I am 24 years of age. I have checked my urinary bladder, liver and spleen and everything was normal according to the scan. I want to talk with an urologist.