Erect penis, pain. Priapus was a Greek god. His main problem was his penis. It was too big. Some penis problems are better than others. I feel so sorry for Priapus.
Some penis problems are serious. When a man's penis becomes erect it enlarges and grows to its full size. This can lead to pain. Medical conditions can cause this.
Painful erection causes. A medical problem may be responsible. There are many possible causes of painful erections, some rare and some common. Understanding the cause is the first step.

Peyronie's disease
Sleep disorders
Penile injection
Vacuum devices
Peyronie's disease. When researching penile pain upon erection in the medical literature, one cause is Peyronie's disease. Let us take a look.

Note:This causes pain in the penis when erection occurs and the penis fills with blood. This is often on one side of the shaft.

Curved Penis

As the fibrous tissue does not stretch during an erection, one side of the penis will not increase in length, and the penis will bend towards the side which is thickened.

Guide to Sexual and Erectile Dysfunction

Peyronie's, pain upon erection. Peyronie's disease is characterized by pain on erection. But over time this symptom will abate. Men may no longer feel pain.

Instead:Men with this condition will have trouble getting an erection in the first place.

And:This is termed erectile dysfunction. The cause of Peyronie's disease is unknown. It occurs most often in men in their forties.

Men with Peyronie's disease experience penile pain on erection, and after a long time, some men will feel no pain but often have difficulty achieving an erection. This may be because of sub-normal blood flow in the penis.Guide to Sexual and Erectile Dysfunction

Peyronie's research, continued. From the book "Contemporary Treatment of Erectile Dysfunction: A Clinical Guide" we learn that less than half of men with Peyronie's disease have pain.
Penile deformity, curvature:

52% of men

Penile pain:

40% of men

Penile lump:

21% of men
Peyronie's sign. Also with Peyronie's disease, many men have a sign called Dupuytren's contracture. This sign is seen on the man's hands (not his penis).

Hands:This means the hands have some fibrosis that limits movement in the same way that the penis is thickened and resists erection.

Erectile Dysfunction: Clinical Guide
Peyronie's diagnosis. A medical test called Duplex Dopper ultrasound is the state-of-the-art for evaluating men who may have Peyronie's disease.

And:An injection of alprostadil is used to improve the imaging quality. This is a medical requirement.

Sleep erections. This is a cause of penile pain while erect. Some men have a condition called "sleep-related painful erections." These erections occur during one stage of sleep—REM sleep.

And:These painful erections cause the man to repeatedly wake up. This makes the quality of his life much worse due to sleep deprivation.

Antidepressant:The painful erections can be reduced with an antidepressant. Something like Zolofy or Paxil may be used.

This is a rare condition that often begins after the fourth decade of life and progressively worsens with advancing age. It is not associated with any physical abnormality of penile disorder or pain during sexual erections while awake.

Sleep Medicine: Essentials and Review
Sleep, continued. In the book "Sleep Medicine: Essentials and Review" we learn that no treatment or therapy is usually required for painful erections while sleeping.

Note:Some medications, including propranolol and Paxil have been used with success.

Medications:Propranolol is a beta-blocker medication. And Paxil (paroxetine) is an antidepressant.

Paxil: antidepressant
Sleep erections, continued. Antidepressants help with painful nighttime erections. But this problem is not considered psychiatric.

And:In the textbook Sleep Medicine, we find that "psychiatric problems appear to be no more frequent than in the general population."

Sleep Medicine
Phimosis. Another diagnosis related to penile pain is phimosis. This diagnosis is often used as a reason to circumcise boys and men.

Prepuce:In circumcision, a doctor removes the foreskin from the penis. Prepuce is another word for foreskin.

Note:The preputial opening is the opening of the foreskin. I researched phimosis in the "Handbook of Urological Diseases in Children."

Phimosis is the inability to retract the prepuce after puberty due to a narrow preputial opening.

Handbook of Urological Diseases in Children
Phimosis continued. For painful erections during sleep, the foreskin can get in the way. This is noted in the book "Sleep Medicine: Essentials and Review."

Phimosis:This is listed as a diagnostic alternative for sleep-related painful erections.

Info:True phimosis is considered rare and only occurs in less than 1 out of 100 boys before age 16.

Penile injection. One result of prostate cancer and prostate surgery is a reduction in erections. A therapy involves injections into the penis to achieve an erection.

And:Several medications are used for this effect, including papaverine (Pavabid) and phentolamine (Regitine).

Penile injection, continued. With penile injections, there may be pain at the injection site. There may also be bleeding on the penis where the injection was done.

Prolonged erection:If the medication dosage was too high, a "prolonged erection" will become painful.

Warning:These injections may also cause Peyronie's disease to develop. They should be used only under strict medical guidance.

One side effect is that if the injection is too strong, it can produce a prolonged erection that may require medical therapy to be relieved... the worst is that in some men, over time, painless, fibrous knots of tissue build up in the corpora cavernosa.

Dr. Patrick Walsh's Guide to Surviving Prostate Cancer
Vacuum devices. Another cause for erection pain on the penis are vacuum erection devices. These devices have medical uses for men who have an inability to attain an erection.

And:Vacuum devices are sometimes used for non-medical purposes. I would not know anything about this though.

Vacuum, continued. In the book "Dr. Patrick Walsh's Guide to Surviving Prostate Cancer" we learn more about vacuum devices and why they can cause painful erections.

Note:The devices are rough on the delicate skin. The penis did not evolve to be vacuumed.

Penis, Numb

The penis is usually cold and sometimes numb, and from the man's standpoint, the erection is often less than desirable... Vacuum devices have few complications; these can include trouble with ejaculation, pain in the penis, and tiny, pinpoint-sized bruises.Dr. Patrick Walsh's Guide to Surviving Prostate Cancer

Chordee. This is another part of penis health. Chordee is characterized when the penis is bent slightly in one direction—up, down, left or right—during erection.

Chordee occurs when the urethra... is shorter than the penis. This makes the penis bend, especially when erect.

Chordee, continued. The word chordee today means a curvature in the penis due to the penis being longer than the urethra. The urethra is too short.

Causes:Unknown or congenital causes may also contribute to chordee. Sometimes this diagnosis is also used to refer to painful erections.

Priapism. This is a painful and prolonged erection of the penis. This can have high or low blood flow. Priapism is a medical emergency.

Medications:Many medications can increase the likelihood of developing priapism. Antidepressants (see below) are a possible cause.

Priapism is a rare event. However, various medications and medical conditions may increase the risk.

Acute management of priapism in men
Antidepressants, priapism. One cause of priapism is psychiatric medications including antidepressants. A man with this side effect should immediately visit the emergency room.

A 58-year-old man experienced priapism several hours after inadvertently taking three tablets of citalopram 20 mg, which he had mistaken for aspirin, in addition to his usual dosage of 20 mg twice/day.

Citalopram-induced priapism
Overuse. Not all causes are due to a serious medical issue. Overuse of the penis for sexual activities may also cause soreness or pain during an erection.

Tip:This is a good reason to stop having sexual intercourse for a few hours or even days.

Tip 2:If a man rubs his penis too much, it will respond like any other sensitive tissue. It will become sore and even painful.

Skin inflammation. Certain irritants on the skin could cause inflammation. This would then create a painful erection. The pain would be the outer part of the penis.

Tip:Avoiding any harmful or irritating lubricants on the penis is advisable. Be careful with what you masturbate with.

And:Using a safe lubricant when engaged in sexual activities will help avoid this sort of pain in the future.

Priapus. Let us return to Priapus from Greek mythology. The word "priapism" is derived from this particular myth. I recommend the Wikipedia page—grow your knowledge.

In Greek mythology, Priapus was a minor rustic fertility god, protector of livestock, fruit plants, gardens and male genitalia.

Priapus: Wikipedia
A summary. There are many causes of painful erections. For symptoms that resemble priapism, a visit to the emergency room is advisable.
Some considerations. For less serious symptoms or chronic problems, there are fewer options to consider. If the problem is severe or severely troubling, a urologist would be able to help.