David Cameron has spoken of having a bad back while holidaying in Scotland. Whatever we think of the prime minister, many of us will wince in sympathy. He doesn't know what set it off, but says that it has stopped him crawling through the heather to stalk deer, as he usually does when visiting Jura. He was offered an epidural injection into his back but is bravely waiting to see if it clears up naturally, and has left the island with its handy supply of good quality malt whisky, to continue his holiday in Cornwall. Is he being over-optimistic about bouncing back quickly?

Back pain is one of the most common problems I see as a GP. The first time you get it is very scary. It can, like Cameron found, come on unexpectedly and with no obvious trigger. Many people say just a small awkward movement like picking a sock off the floor results in a sudden searing pain on one side of the lower back. This can settle into a dull but nagging ache in the same location, or shoot down the legs.

The vast majority of people who get a bad case of back pain will not have a serious underlying cause and will be better within six weeks. You'll be advised to keep mobile (walk a bit every day, even if it hurts) and take painkillers. Having an epidural spinal injection involves squirting some steroid into the space outside the sac of fluid around the spinal cord. This provides short-term relief of the pain for over half of the people who have one, though no huge improvement in others but doesn't make you heal more quickly.

The reason back pain hurts so much is because there is pressure on nerves as they exit from the spinal cord. In some cases, the outer shell of the disc that sits between bony vertebrae splits, so its gel-like core bulges outwards and sits on a nerve. This is called a slipped disc.

The evidence seems to suggest that it makes no difference what action you take, if any. After six weeks, you should be back to normal, whether you've done nothing, taken bucket loads of painkillers, had an injection or undergone an operation. I won't be thanked for saying this, but research also seems to show that no intervention substantially alters the outcome. So physio, osteopathy, chiropractic, Alexander technique and other disciplines can help pain relief and possibly help to prevent recurrences of back pain by encouraging good back care, but don't appear to improve recovery times from an acute attack.

People worry, understandably, that their back pain is so painful that it must be a sign of a dangerous underlying condition, like osteoporosis or cancer. But the chances of this being the case are less than 5%, and even less likely if you're under 50 and in generally good health.

Symptoms that set off alarm signals in a doctor's mind are when back pain is intractable, worse at night or accompanied by unexplained weight loss, fever or loss of bowel and bladder function. Because most back pain is felt in the lower back or neck, pains in the middle section of the spine may need further investigation.

So what would I do if I were David Cameron? Resign? Change my ways? Maybe, but that sort of advice is beyond my pay grade. Specifically, if I had had a bad back while on holiday, I'd have stocked up on paracetamol and ibuprofen, then forced myself out for a gentle walk every day, stopping to admire the scenery and the wild deer running freely and unstalked. I would have eschewed cycling or climbing Munros in favour a distillery tour and allowed myself a nip of the free samples (though easy on the whisky with multiple painkillers). If I'd started improving after a week and was gradually getting better, I wouldn't bother with scans or injections. I'd be confident of a speedy recovery – and wouldn't let it stop me from running the country.