If this is a serious question, see a urologist.
I'm not a doctor, and don't play one on TV, know just enough to be dangerous. I did take a very interesting adult ed course at the local university, Men's Health, essentially urology for laymen, taught by a retired urologist.
There are several causes and treatments for ED. The treatments vary in their efficacy and cost. The pills can work well until they don't. The most interesting was an implant that can be pumped up, erection on demand. The really interesting part was that the doctor mentioned studies that showed over 90% satisfaction for both "owners" AND their partners. Cost at the time was about 20 grand.
Another interesting story, apparently true, is that the developer of the injectable ED medicine gave a presentation at a professional conference, at which he whipped it out and gave a demonstration on his own dick.
