Sex feels good. That's why we do it.

Oh, sure, there's that whole procreation thing, but having babies is not all there is to it. Just ask sexually active people who are past their reproductive years and same-sex-attracted people—or anyone who's ever masturbated.

Feels good, man.

But when orgasm brings pain along with pleasure, it's troubling.

Surprisingly common, painful ejaculation affects up to 25 percent of men, according to a meta-study published in the journal Cureus. It can cause distress and affect quality of life, including sexual function.

"It's a significant problem for guys because it can cause a psychological effect, a sort of fear of sexual activity, fear of ejaculation," said Neel Parekh, M.D., a male fertility specialist with Cleveland Clinic.

What causes painful ejaculation? 6 possible culprits 

Painful ejaculation can be caused by a variety of factors. Here we look specifically at a few of the causes of prostate pain after ejaculation—including one often mistakenly blamed on the prostate—and what you can do about them.

Prostatitis ejaculation pain

The most common urologic malady affecting men younger than 50, prostatitis is the inflammation of the prostate gland. It can cause difficulty with urination, erectile issues and general pain throughout the genital region.

When a man with prostatitis ejaculates, the spasms and contractions of the prostate gland can intensify whatever discomfort he's already feeling. Those contractions can cause sharp pangs deep in his pelvis, beneath his genitalia, near his rectum or in his perineum, the area between the anus and the genitals.

Treatment for prostatitis varies depending on which type is present, bacterial or nonbacterial.

Chronic prostatitis or chronic pelvic pain syndrome

Interestingly, what's frequently thought to be prostatitis at first could turn out to be something slightly different.

"We are finding out recently that many of these patients with 'prostatitis' have pelvic floor muscle dysfunction, which can feel like a pelvic floor muscle spasm," said Amy Pearlman, M.D., the director of men's health at the Carver College of Medicine at University of Iowa Health Care.

The pelvic region is well known for giving men something called "referred pain." That's when pain in one body part is registered as pain in a nearby body part. Pain in the bladder or prostate might register as testicular pain or penis pain, for instance. Pelvic floor muscles are increasingly being recognized as the culprit behind a host of issues related to male sexual health.

"Prostatitis and prostate infections can cause painful ejaculations," Parekh said. "But more often than not, what we see is chronic nonbacterial prostatitis or chronic pelvic pain syndrome [CPPS] being the cause. When the pelvic muscles are tight, those are the same muscles that contract during ejaculation. So when you ejaculate, you're contracting an already tight muscle, which causes further pain and discomfort."

Luckily, once an infection has been ruled out and CPPS has been identified, it's a relatively straightforward path to getting relief for pain after ejaculation. 

"I've seen many men with painful ejaculation in the last four years and have treated maybe two with antibiotics," Pearlman said. "The rest are sent to pelvic floor physical therapy, and many of them get significantly better."

Enlarged prostate

Benign prostatic hyperplasia (BPH), or an enlarged prostate, can also sometimes be a cause of discomfort during ejaculation. Just as urinary flow may be constricted when the swollen prostate pushes against the structures of the urethra, so, too, may the flow of semen be restricted during orgasm, causing prostate pain after ejaculation.

BPH can often be successfully treated using a variety of medications, including alpha blockers and tamsulosin (brand name Flomax).

Prostatic cyst

A rare condition in which a cyst develops on the ejaculatory duct can be a cause of painful ejaculation as well. Semen travels through the ejaculatory duct during an orgasm, and if a cyst is there restricting the flow of ejaculate, pain can be the result.

The cysts are similar to kidney stones and, while usually benign, can lead to complications such as urinary tract infections, post-urination incontinence, recurrent epididymitis and blood in the sperm.

These cysts are usually diagnosed using MRI scans or transrectal sonography and may be treated by transurethral resection, which is surgery performed via an instrument inserted through the urethra. Certain types of larger cysts may require open surgery or laparoscopic surgery to remove.

"I've seen a few prostatic cysts in my practice, but it's not something you see very often," Parekh said.

Blocked ejaculatory duct

On rare occasions, the ejaculatory duct can become partially or completely blocked, resulting in painful ejaculation. The blockage can be caused by cysts, as outlined above, or by a groin injury, inflammation or scarring.

Surgery is usually needed to remove any such blockage.

Prostate cancer

While prostate cancer is considered more or less asymptomatic until it metastasizes to other parts of the body, it nonetheless can cause pain during ejaculation, according to Cleveland Clinic. If the tumor is big enough to press on the urethra, it can restrict the flow of semen during ejaculation and cause discomfort. It can also cause hematospermia (blood in the semen), decreased ejaculate volume, erectile dysfunction (ED) and urinary issues.

Fortunately, modern medicine has progressed to the point where experts can diagnose and fix a wide variety of the causes of painful ejaculation. The first step, as always, is letting your healthcare provider know what's going on.