The numbers are nothing short of staggering. Nearly one-third of all Americans — 100 million people — suffer from chronic pain, according to the American Academy of Pain Medicine. That is more than those suffering from diabetes, heart disease and cancer combined.

Little wonder that pain — and specifically the drugs to manage it — is a big business, totaling $24 billion in the U.S. alone, according to an analysis by Mizuho Securities. With that kind of money at stake, and with demand for the drugs so high, the temptation for doctors to overprescribe them can be great.

"I think it has become a problem in this country," said Orly Avitzur, M.D., medical director at Consumer Reports. "It's come to a point where sometimes we're doing more harm than good."

Los Angeles physician Lisa Tseng took that to a deadly extreme. In 2015, she became the first doctor in the United States convicted of murder for recklessly overprescribing drugs. As told on the latest episode of CNBC's "American Greed," her clinic handed out some 27,000 prescriptions in just three years. At least 13 patients died in her care.

But even legitimate, well-intentioned doctors can fall into the overprescription trap. A study last year by the National Safety Council found 99 percent of the doctors surveyed were prescribing highly addictive opioids for longer than the three-day period recommended by the Centers for Disease Control and Prevention.

"Most doctors don't want to see anyone suffer, so it is our instinct to really try to help people," Avitzur said. "At the same time, we're very busy nowadays in practices, and patients don't get the same face-to-face time that perhaps they did 10, 20 years ago. And so in a way it's easier to write a prescription than to have to go into a lengthy discussion about why I'm not going to write you a prescription."

How can you tell if your doctor is an over-prescriber? Avitzur offers some tips on how to recognize and address the problem.

A pill for every ill

Prescribing medication is a serious matter, and your doctor should treat it that way. That means explaining the drug, why it is being prescribed and the potential side effects.

"If you leave a doctor's office and you have a lot of prescriptions and you don't know why, that's one of the tipoffs that you may be getting more medication than you need," Avitzur said.

Do not be afraid to ask your doctor why he or she is prescribing a drug. Also, do not hesitate to ask if there are alternative treatments that do not involve medication. For example, there are many ways to address cold or flu symptoms, and not all involve medicine.

"We're sneezing, or we're coughing, or we have a sore throat, and they can also be managed with just a lot of rest and fluids and ways to just really treat the individual symptoms, as opposed to prescribing something like an antibiotic," Avitzur said.

Writing on the wall

Despite various reforms in recent years, pharmaceutical companies still market their products directly to doctors. There is nothing wrong with that as long as your doctor maintains some perspective.

"Pharmaceutical representatives who come to a doctor's office often bring little notepads or pens or clipboards with their logos on it, and they're telltale signs for a patient that they've been there," Avitzur said.

Too many trinkets on the desks or logos on the wall could be a sign that your doctor is focused too much on the marketing messages and not enough on your well-being. Again, do not hesitate to ask questions, particularly if the prescription is a little too closely matched to the marketing materials around the office.

Questions and answers

Questioning your doctor may feel awkward, but it can actually be one of the most effective ways to determine whether there might be a problem. Your doctor should welcome your questions.

"Doctors are very happy to receive that kind of conversation because they want you to be safe, they want to know that you're taking things correctly and they welcome a discussion of alternatives," Avitzur said. "If in turn, your worst fear is realized and your doctor dismisses you or doesn't address your concerns, then it's probably time to find another doctor."

Do your part

Finally, remember that you also have a role in preventing overprescription. Pharmaceutical ads are flooding the airwaves these days, almost always urging you to "ask your doctor" about the latest treatment. Of course it is fine to ask, but insisting that your doctor prescribe the medication you saw on TV puts him or her in a difficult position, and opens the door to drugs being overprescribed.

Similarly, insisting on antibiotics to treat cold symptoms is a bad idea.

"You have to understand that your cold is very, very likely caused by a virus, and antibiotics have zero effect on viruses," Avitzur said. "Not only that, but in doing so, you risk contributing to a growing problem today, which is that of antibiotic-resistant bacteria."

Pill mill doctor Tseng, who is serving a 30-year-to-life sentence in a California prison, depended on addicted patients to enable her crimes. Your doctor is almost certainly not a criminal. But if he or she is an over-prescriber, it can only happen if you let down your guard.

Go inside Lisa Tseng's multimillion-dollar pill mill, and see how authorities finally brought it down, on the next all-new "American Greed" — Monday, March 13 at 10P ET/PT only on CNBC.