On a scale of one to 10, how much does it hurt?

That’s the most advanced tool doctors have for assessing pain.

“It’s challenging,” said Dr. Brian Pierce, a primary care physician at Midcoast Medicine in Rockport and president-elect of the Maine Medical Association. “Chronic pain is one of the hardest things we do.”

One reason is that there’s no test for pain – no full-body scan or blood analysis that can show whether a patient has it or how bad it is. Yet, it’s the primary reason people go see a doctor.

Joint and back pain alone are the second and third most common reasons for an office visit, after skin issues, according to a 2013 Mayo Clinic study. Headaches or migraines also made the top 10.

The first doctor seen by patients with pain usually is their primary care physician.

Pierce said there are different things he does in exams to determine the severity of pain and its effect on his patients’ ability to function – looking at how they walk, what their range of motion is and whether it’s consistent when the exams are repeated.

But he also relies on what he learned about his patients over the years, using the context of their lives and their medical histories to help determine the cause and severity of their pain, as well as how it should be treated.

“I’ve got lobstermen who need to lift their traps and people who just want to get around the house,” he said.

The other problem with pain is that it’s entirely subjective. That one rudimentary tool – the 1-10 scale – is different for everyone and means nothing other than what the patient perceives the relative level of pain is.

Dr. Stephen Hull, medical director at the Mercy Pain Center, said he’s had patients label their pain as a 15 on the scale. He would think that would mean they’d be writhing on the floor in agony, yet they’re sitting still in a chair in front of him, he said.

That doesn’t mean he dismisses the answer. Hull said it’s an indication of how they feel about their condition.

There are people who try to take advantage of the subjectivity of pain and the fact it can’t be proven by faking it to get prescriptions for narcotics, which they abuse or sell to other drug users.

Conversely, doctors can be overly suspicious that patients are so-called “pill-seekers” and end up denying medication to people who would genuinely benefit from it.

There also appear to be cultural, racial and gender-based components to pain perception and pain treatment.

Black people are less likely than whites to get prescriptions for narcotics, which may be a reason that they report higher levels of pain in general, according to a federally mandated report on pain done by the Institute of Medicine in 2011.

Asians, meanwhile, report a higher tolerance for pain, possibly because their culture values stoicism and because they might not say when the treatment is not working out of respect for the doctor, the report said.

Women have a lower tolerance for pain than men, the report said, attributing the distinction to fluctuations in female hormones and a social stigma against men complaining about pain.

Experiences from childhood, general health and genetics influence every person’s pain tolerance. One’s attitude about the pain can also affect how it’s perceived. Feeling hopeless that pain will never ease can make it hurt more.

Pierce, the Rockport doctor, said when he gets new patients complaining of pain – which he does once or twice a week – he often sends them to a specialist, like a neurologist or a back surgeon, to determine if there’s an underlying cause. If not, he said, he might refer them to the physiatrist, or rehabilitation physician, that his practice added to its staff a couple of years ago.

“There’s not a lot of pain specialists compared to the demand,” Pierce said. “Often, patients will have to travel quite a bit and wait to get in.”

The Institute of Medicine report said, at the time, there were about 3,500 board-certified pain specialists in the U.S. and 100 million chronic pain patients.

The report calls for doctors in the country to treat chronic pain as “a disease in its own right,” taking as much care to relieve it whether the patient has cancer or doesn’t know the cause.

A lack of diagnosis has often led medical professionals to dismiss the pain or blame the patients, labeling them liars or hypochondriacs – and leaving them helpless against a pain that’s taken over their lives.

“The reality is,” Hull said, “nobody really understands pain like a pain patient does.”