Medical science is a wonderful thing when it's working well. So if you break a bone, doctors are very good at splinting it (or covering you with plaster to stop you moving around too much) and waiting for it to knit back together again. The mechanics of how to deal with this situation are well understood. But if you ask doctors about why it hurts, no-one can really explain how the pain system works. For the record, the word "pain" comes from the Greek for penalty. Pain is a type of punishment for your body failing. As to the nervous system, there are nerve endings all over your body and when a stimulus passes a threshold, this is interpreted as pain. Under normal circumstances, the pain will be localized, i.e. there will be pressure or an injury that triggers the sensation. But there is also "referred pain" which is where pain from one part of the body is felt in a different part, e.g. pain from the gallbladder is often felt in the right shoulder because the nerves are distributed by the same root in the spinal column. This is confusing when it comes to diagnosis.

When the stimulus generates the pain message, it is transmitted to the brain. This depends on the neurotransmitters, yet it is still not certain how everything works together. One thing is clear. Pain is pain, and it does not matter whether it is classified as acute or chronic, i.e. short-term or likely to last a long time. The real difference is that the cause of acute pain is often clear, e.g. you broke a bone, so you know it will heal. But the causes of chronic pain may not be clearly identified. Nevertheless there are a number of approaches to deal with the problem. There are drugs from the pharmaceutical companies. You start with aspirin for the less serious pain and work up to the seriously powerful opiates that will knock you out and kill all but the most severe of pain sensations. The majority of the drugs come in a pill or capsule, but there are also topical creams you can rub on to the affected parts of your body and, in the more extreme cases, there are injectable versions that deliver the drugs close to the point where they will do the most good.

Holding the middle ground is tramadol. This is a opioid, i.e. it has the same general effect as an opiate, but is synthetic rather than produced from a natural substance. This drug is now the first response used by doctors for moderate to severe pain. It's not completely clear how or why it works except that it affects the levels of neurotransmitters. The brain therefore becomes less aware of the pain. This gives relief and, if the pain is acute, you have greater peace while the cause of the pain is treated and heals. For chronic pain, tramadol is equally effective but there are two issues. The first is you should not take too high a dosage over too long a time. This can be habit-forming. The second problem is psychological. The acute patient knows the pain will stop fairly soon. It is harder to maintain a good quality of life if the pain is chronic.