Sudden back pain: does how much it hurts show how serious it is?

In a 2021 video on the French YouTube channel Major Mouvement, a physiotherapist and manual therapy teacher who goes by Grégoire talks about the back that suddenly locks, "le dos bloqué", which French speakers often call lumbago. A muscle that tightens, Grégoire says, can hurt extremely. Grégoire has written a book and teaches manual therapy courses for health professionals, both promoted under the video. Then comes what Grégoire calls the good news about it. In that video:

"l'intensité de la douleur ne révèle en rien la gravité potentielle de la lésion"

(Our translation: "the intensity of the pain reveals nothing about how serious the injury might be")

Grégoire, Major Mouvement, 2021

What works best in that moment, Grégoire goes on, is moving.

Loud isn't harm

When your back goes, it's natural to read the volume as a measure of damage. The worse it hurts, the worse it must be. Grégoire's point is that, for this kind of sudden flare, the two don't track each other. The pain can be loud while what's behind it is ordinary.

Public advice in the UK puts it plainly: the spine is strong, and back problems are rarely due to any serious disease or damage (NHS inform, 2026). Researchers who asked people with back pain and clinicians to define a flare described it as a worsening that lasts from hours to weeks, is hard to tolerate, and gets in the way of the day (Costa et al, 2019). Then it passes.

The longer course is encouraging too, on average. In a 2024 review of studies that followed people with new low back pain, average pain fell from 56 to 26 out of 100 within six weeks (moderate-certainty evidence). For people whose pain had already lasted for months, it eased far more slowly (Wallwork et al, 2024). These are averages, not a promise for any one back.

Where "nothing" goes too far

"En rien", nothing at all, is strong. Right after the quote, Grégoire calls it entirely benign. This article doesn't go that far, and neither does the program it belongs to: how much it hurts says little about how serious it is, but a few signs do change the picture. That's why they're checked first.

Most flares pass, but a few signs mean more. If any start, get help:

Get medical help straight away

• Trouble peeing, or leaking pee or poo without meaning to
• Numbness around your genitals or bottom, or sex feeling different
• Both legs weak, numb or tingly, or you can't walk because of the pain
• Pain after a serious fall, accident or blow
• Chest pain or trouble breathing with it; or new pain far worse than before, or getting worse fast

See a doctor first

• A fever, or feeling hot, shivery or unwell
• Cancer in the past, or weight lost without trying
• Pain worse at night or unchanged by moving or resting; high between the shoulder blades; one leg weak or numb

If a new flare isn't getting better after a few weeks, keeps getting worse, or worries you, see a doctor.

The rest of Grégoire's video is a routine of five movements. This program doesn't ask you to do it.

How this fits the Manage back pain program

In the 1h Protocol to Manage Back Pain, chapter 4, "When your back goes", plans the first hours of a flare, a smaller day you can still keep, and one line in your own words. Your flare card, saved for your lock screen, opens with the same idea: "Loud isn't harm. A flare passes." It also points you back to the warning signs. The first chapter is free.

Source: Major Mouvement, LUMBAGO : Comment soulager un mal de dos aigüe ? (Quick fix #1), 22 Sep 2021 Research: NHS inform, 2026 · Costa et al, 2019 · Wallwork et al, 2024