I'VE BEEN having these strange pains in my head. They are concentrated in small spots around the ears. Thank God I read a newspaper piece about mobile phones and brain tumours otherwise I might never have noticed. And as for the pains I get when I write about breast cancer! You just don't know.

Well actually you do, because apparently for the reader hypochondria can be even more scary. So, at the end of breast cancer awareness month, it is worth remembering that most of us are perfectly well. It is easy to think that an early death is inevitable; that if cancer doesn't get you, pollution, CJD or a heart attack will. Media and public interest in disease inevitably focuses on the tragic, the young and the painful. We tend to forget that this is the healthiest and longest-lived period in human history.

"People can't judge probability," says Dr Eamonn Ferguson, senior lecturer in psychology at Nottingham University. "People overestimate low risk events and underestimate high risk ones." (Otherwise no one would buy a lottery ticket). "The reason is that the brain remembers vivid events like someone young dying of cancer or an aeroplane crash."

The risk of getting breast cancer over a lifetime is one in 11 (but doesn't it sound better if you tell yourself that you are 91 per cent unlikely to get it?). However, that includes all the people who get the disease at 85 and the ones who have a lump removed and then recover. The actual risk of dying of breast cancer before the age of 40 is just under one in a 1,000. And brain tumours? Hardly anyone gets one. Not even Woody Allen. It just seems common because if anyone gets one everybody hears about it.

Our health panic is fuelled by good intentions: health education messages that need to be fairly scary or no one will take any notice; newspaper articles that try to keep people reading. We believe that it is normal to feel well all of the time because the smily people in advertisements are always glowing. People in Casualty never get indigestion. In the media world you are either wonderful or hanging on by a thread.

But real life is full of non-events. Dr Ingvard Wilhemsen at the University of Bergen in Norway says that in any one week 80 per cent of people have unexplained pains which are nothing at all. We worry because we are in an unfortunate state of half-knowledge. We are more knowledgeable than previous generations; we know that people get brain tumours and that doctors can mis-diagnose, but we don't know enough to reassure ourselves.

It is absolutely possible to feel pain when nothing is wrong and not to feel pain when damage has been done. "People can feel more pain at the dentist if they are afraid," says Dr Paul Salkovskis, hypocondriasis expert at Oxford University. "But then there are accounts of people coming off the battlefield with bullet holes through their hands, laughing because it doesn't hurt."

Hypochondria can itself cause pain. "If you have a fear of Hodgkin's Disease," says Dr Salkovskis, "and you know that one of the symptoms is enlarged glands, the anxious checking you do may mean by the end of the day, you do have enlarged glands." This can be used to help people. Dr Salkovskis encourages patients to worry as much as possible and watch how this can bring on the sensations.

The good news is that there is no established link between worrying about cancer and getting it. Actually, hypochondriacs are less likely to get ill because they look after themselves. The compromise that we need to reach is to remain vigilant but not worry. We want to have control over our lives but we can't so we might as well be cheerful. For, as Dr Wilhelmsen says, there are no medical certainties to give the hypochondriac. "Nothing is 100 per cent certain except dying, which isn't exactly a comfort." Just take deep breaths.