I can not empty my bladder all the way

Patient: I have been clean off heroin for four years but still experinceing trouble urinating can this be caused from past drug use

Symptoms: I feel link I can never empty my bladder fully I have a somewhat week stream and at the end I have to push and strain to try to force it all out. I feel mild pressure above my pelvic bone as well. A lot of times I finish urnating stand up then have to sit back down to try push out more it always feel like I have to go