Really weird "injury", anyone experienced the same?

[Tiedemies]

So,
Yesterday I did a workout which included benching and in the evening I felt a bit of tightness in the chest muscles. Didn't think much of it, until at some point I was "streching", not really deliberately, but I was yawning and had my arms behind my head, you know the normal thing you do semi-voluntarily, pushing my elbows and shoulders back. I also had a slight rotation in my thoratic spine at the time. So, during thins yawning/streching movement, which was pretty much not consciously started, I felt something like a tear or a rip or a pop in the area where my pec attaches near the lower parts of the sternum. And it hurt quite a bit.

And when I woke up this morning, that place is damn sore. It is not in the pectoralis muscle, it feels like it is something to do with the left side of the sternum. Rotating my thorax to the right hurts the area. The pain is dull, not really sharp. It doesn't hurt unless I rotate to the right. I am guessing it had more to do with the cartilage between the sternum and the ribs and the fact that it appeared after the workout is just incidental.

I am just curious if anyone has ever experienced something like this.

[Tiedemies]

Update: The problem subsided within 2 days. I was able to squat yesterday and today I don't have the pain, just mild discomfort on the left side of the sternum if I rotatate my thorax to the right.
Funny thing. Can't figure out what it was that "popped", but it seems it wasn't anything serious.