I am 19years old , and two years ago i face a injury to my testicles, the urologist said everything was normal and an ultrasound also didnt show anything but since then i dont get proper erections , i cannot get a erection by visual stimulation and even after physically touching my penis i only get semi erect. Morning erections have never happened since then and whenever i get semi erect by touching myself it goes back to normal within secs. I am really worried pls help.