Pain quiz: Do you believe the myths?

In some cases, pain serves a good purpose. It warns you that something is wrong — for instance, you're burning your hand — and makes you withdraw reflexively, before the hot dish you've picked up does any real damage. However, persistent pain provides no useful warning. It distracts you and curtails your activities, leaving you frustrated, tired and depressed. By trying to "tough it out," you may be compounding your problems, rather than getting stronger.

Not all pain is associated with a detectable injury or disease. Many people are quick to assume that if they have a pain, some specific abnormality must be causing it. And they're almost equally quick to assume that if an abnormality is present, it can be cured with an easy intervention. But this isn't always the case.

Chronic pain may be particularly difficult to trace to a specific cause. And even in conditions in which there is damage to the body, the amount of damage often does not correlate with the amount of pain a person feels.

Pain is more common as you age. And pain is common in some illnesses. But pain isn't inevitable. Regardless of your age and medical condition, if you're in pain, you should ask your doctor for treatment. Pain control helps you heal faster and promotes a better response to other treatments.

When used correctly, opioid medications — also known as narcotics — can be very effective. While it's true that over time, you may need a higher dose, or a different medication, for the same pain relief, this tolerance does not mean you're addicted. Similarly, physical dependence, which means you have withdrawal symptoms when you go too long without a drug you've been taking regularly, differs markedly from addiction.

Addiction is defined as the obsession with taking a drug against medical advice and despite the fact that it is having harmful effects on physical, mental and social health. Most people who use opioid medications for pain under the direction of their doctor never become addicted.

It's common to develop a tolerance to pain medication, which means you'll need higher doses to achieve the same level of pain relief. In some cases, tolerance proves to be helpful, as many of a drug's side effects — such as sedation — may disappear once your body becomes used to the medicine.

The dose of morphine and other opioids can be gradually increased as much as is needed. Unlike most other medications, there is no upper dose limit for opioids. However, in some cases, increasing tolerance may be an indication that a given medication is not suitable for the problem at hand.

Many people mistakenly associate morphine with a terminal condition. This is partly because of the widely believed — but incorrect — idea that a "lethal dose" of morphine is the only way to stop serious pain just before death.

Morphine can be helpful for people in hospice care at the end of life, but it's also effective for painful conditions that aren't life-threatening. For example, morphine is commonly used to control pain after surgery.