Sorry to hear you are dealing with this. This is a fairly common form of sexual dysfunction. This article is really long and technical. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6127532/ But it does have a lot of info in it. Your doctor has not been informative at all? One thing I know comes up when you are being assessed is your emotional state. Have you been depressed? Are you anxious? That can impact this. To clarify, you have ejaculation but not orgasm with it? I'd also get your prolactin level checked. There also seems to be some association when someone has a neurological condition. Get your testosterone checked and do kegel exercises. But mostly, talk to your doctor.
Does prolactin have an effect you say?
You don't say exactly how this is manifested. Are you saying you can ejaculate but it doesn't feel good? There are many reasons this can exist. One is caused by medication, including medication often used to treat some of these problems like SSRI antidepressants. So one thing to look at is if you're taking medication or if you were when the problem started. I was on SSRIs for a long time, and it caused me to take a really long time to ejaculate. I did have the pleasure of it, but it could take forever. But the problem didn't go away when I stopped taking those drugs, so what I'm suggesting here is one place to look is medication as effects can outlast the taking of them. This is because of another possible reason, which is the brain to genitalia connection isn't working right. Medication can cause this, but it can be caused by unknown factors. I would assume a neurologist would be the person to see about it, but you doc should be able to direct you to the right specialist. This by no means replaces what was said above, it's great info.
Sometimes it happens and sometimes it doesn't and when it does happen it is very delayed relative to ejaculation leading be to believe it is a nerve issue. Thanks for your response.