In Canada (and possibly elsewhere), there are back pain relief medications called Robax. They have a series of long-running commercials featuring wooden marionette-type people. In them, the marionettes do something active until needles pop up from their backs, representing back pain. I thought that you actually got needles coming from your back whenever you had too much activity and got back pain and Robax was used to pull them out.
A childhood belief about adverts

others believed things like this
- When I was younger I used to believe that when I hit an object they would feel pain like they were living.— Alice
- dragonfliesw ere called, Devil's darning needles.— davarm
- I used to think when I peed in the shower as a kid, the water coming back through the showerhead was my pee.— gregg
- I used to believe that echos were actually the sound going completely around the world and coming back to you.— kyle
- Whenever I got pins and needles in my legs, I thought that woodlice where crawling around inside them!— squee
- I used to think that a carpool was one of those bug, long limosine's with a pool all the way in the back.— Annie