Popping in Upper Rib Cage?

Lately I’ve noticed a “popping” feeling at the tom of my rib cage. First noticed it doing lat pulldowns but happens pretty much any time I stretch back and take a deep breath. It doesn’t hurt, but not sure if anyone’s experienced it or knows what it could be?

Also, after working abs sometimes it feels like the muscle is “sticking” to the rib cage before popping a bit.

Hope my explanation makes some sense. Like I said, it doesn’t hurt at all, but not sure if it’s something I should be worried about.