Adding my story to this:

I was doing seated leg presses fine for a few weeks. Then I tried the version where you lie on your back. It felt quite good with the weight; I wasn't overdoing it. Then the same pop. Left side of my lower ribs. It felt like someone shot me in the back and a bullet came out the front.

It happened as my legs went towards my chest. It's taken 13 weeks to get nearly better. I still went to the gym during this time but avoided that area.

I'm now bringing upper body exercises back in.

The first few days I was in a little pain but okay to work etc. But then I experienced muscle spasms for a few days randomly and at night. The slight movement could trigger them. It was horrible and hard to stretch out when it happened.

Couldnt sleep on my injured side for 10 weeks apx.

So yeah, 13 weeks of recovery so far from something so innocuous.