Absolutly agree with
@trophywench. You need to speak to your GP and see if you can be refered to an andrologist if they can't help.
I had my prostate removed last year and they could't spare the nerves, so no more spontaneous erections for me.
I can't take viagra because of my hypertension. I now use injections to get erections. Sounds awful but it's no different than taking my insulin.
The doctors have seen and heard it all before, so no need to be embarrased. I know it seems a big step but once you take it, you will wonder what all the fuss was about.
P.S. you don't need an erection to have an orgasm.