1. SUDDEN GROIN PAIN
What it feels like: It’s as if you were kicked below the belt, but the pain is not quite as intense. Sometimes, it’s accompanied by swelling.
What it is: It’s probably called testicular torsion. Normally, a man’s testicles are attached to his body in two ways: by the spermatic cords, which run into the abdomen, and by fleshy anchors near the scrotum.
But sometimes, in a relatively common congenital defect, these anchors are missing. This allows one of the spermatic cords to get twisted, which cuts off the flow of blood to the testicle.
2. SEVERE BACK PAIN
What it feels like: Similar to the kind of agony you’d expect if you'd tried to bench press an armoire. The usual remedies—heat, rest, OTC painkillers—offer no relief.
What it is: “If it’s not related to exercise, sudden severe back pain can be the sign of an aneurysm,” says Sigfried Kra, M.D., an associate professor at the Yale school of medicine.
Particularly troubling is an abdominal aneurysm, a dangerous weakening of the aorta just above the kidneys. If it bursts, you’ll die within minutes.
A less threatening possibility: You have a kidney stone. More pain, but you'll only wish you were dead.
3. PERSISTENT FOOT OR SHIN PAIN
What it feels like: A nagging pain in the top of your foot or the front of your shin that’s worse when you exercise, but present even at rest. It’s impervious to ibuprofen and acetaminophen.
What it is: Probably a stress fracture. Bones, like all the other tissues in your body, are continually regenerating themselves.
“But if you’re training so hard that the bone doesn’t get a chance to heal itself, a stress fracture can develop,”
4. SHARP PAIN IN THE ABDOMEN
What it feels like: All the metaphors apply—knife in the gut, bullet in the belly, skewer in the stomach—except this attack is from within.
What it is: Since the area between your ribs and your hips is jam-packed with organs, the pain can be a symptom of either appendicitis, pancreatitis, or an inflamed gallbladder.
In all three cases, the cause is the same: Something has blocked up the organ in question, resulting in a potentially fatal infection.
Pain in your upper abdomen with high white blood cells usually spells an inflamed gallbladder (goodbye, gallbladder).
And if it hurts below your breastbone and certain enzymes in the blood are elevated, then pancreatitis is probably the culprit. (The pancreas stays, but a gallstone may be blocking things up. If so, the stone and the gallbladder may have to come out.)
5. TRANSIENT CHEST PAIN
What it feels like: A heavy ache that comes on suddenly and then goes away just as quickly. Otherwise, you feel fine.
What it is: It could be indigestion. Or it could be a heart attack.
“Even if it’s very short in duration, it can be a sign of something serious,”
Here’s how serious: A blood clot may have lodged in a narrowed section of a coronary artery, completely cutting off the flow of blood to one section of your heart.
How much wait-and-see time do you have? Really, none. Fifty percent of deaths from heart attacks occur within 3 to 4 hours of the first symptoms. You’re literally living on borrowed time.
6. LEG PAIN WITH SWELLING
What it feels like: Specifically, one of your calves is killing you. It’s swollen and tender to the touch, and may even feel warm, as if it’s being slow-roasted from the inside out.
What it is: Maybe deep-vein thrombosis, or DVT, which occurs when blood pools in your lower legs and forms a clot. Next thing you know, that clot is big enough to block a vein in your calf, producing pain and swelling.
Unfortunately, the first thing you’ll probably want to do—rub your leg—is also the worst thing. “It can send a big clot running up to your lung, where it can kill you,”
7. PAINFUL URINATION
What it feels like: Relieving yourself has become an exercise in expletives, and your urine has a rusty tint.
What it is: Worst case? Bladder cancer, according to Joseph A. Smith, M.D., chairman of the department of urologic surgery at Vanderbilt University. The pain and the blood in your urine are symptoms of this, the fourth most common cancer in men.
Smoking is the biggest risk factor. Catch the disease early, and there's a 90 percent chance of fixing it. Bladder infections share the same symptoms.