Frequent Urination, Difficult To Urinate, No Pain, No Blood, UTI, Diabetes Reports Normal

I am 25 years man and have have been notices some symptoms for the past three years.my symptoms are I I have been urinating more often and been having the urge to urinate more frequently as well and it worst at night, I woke up like four to ten times to urinate every night and even if i take a nap during the day time. i also have it difficult in starting to urinate and need to strain it for some few second in order to start. moreover, I always felt that i have not emptied my bladder even after i ve been to the washroom,There has never been any blood or pain with the urinating. I ve been to the hospital so many time taking other tests like diabetes , urinal tract infection ,OGGT , gonorrhea and other but not a prostate test and results seems everything is ok. Please Doc, what is wrong with me and what are the treatment for it or prescription of any drugs for me.