It was only after moaning about the situation recently to a family friend and former physio that I hit upon the cause. They told me that I was suffering from an acute case of piriformis syndrome. “My piri-what now?” I cried.

“The piriformis muscle is a small, deep muscle located in your bottom,” Anisha Joshi, principal osteopath at Osteo Allies, tells Strong Women. “And for some people, the sciatic nerve runs beneath or through the piriformis.”

Bingo. The pain was being caused by this hitherto unknown muscle pinging my sciatic nerve. We’re way more familiar with sciatica; it’s estimated that around 40% of Brits will suffer a bout at some point. Might some of that sciatic soreness actually be caused by the piriformis? That’s certainly been true in my case, so I’ve been spending the past few weeks trying to work out how I can fix my creaking lower back and get rid of chronic pain once and for all.

This tiny muscle is a common cause of lower back pain (and you’re probably not even aware of it)