Just like when you crack your knuckles, I often times feel the need to crack my chest.
It's not the center of my chest, but more of on the right side/corner is where it cracks. I've had this for quite awhile now (maybe less than a year).
It has been better going Paleo, especially with inflammation in chest going away, but I'm wondering do I just not crack it, and wait for it to heal? Or do I keep cracking it? If I don't, it feels like tension builds up, and then it kinda hurts to crack it the longer I wait.
I know of a physical therapist who calls this a subluxed rib. He says that if your try hanging from a pull-up bar with hands in chin-up position. Sometimes this helps. I have no links or sites - this is just what he says to me verbally.
I have a rib that gives me problems but only have popping first thing in the morning after a heavy chest lifting session and I consider it almost unrelated. The rib issue may or may not be due to "subluxation" but I know it can come and go easily and the pain can be quite severe. It usually concentrates as a sharp pain in the back but I also sometimes get a dull ache around on the chest side. Usually making a barrel shaped chest (hands behind head, elbows out, deep breath, arch back) tends to put things back where they belong.
P.S. If there is no pain I wouldn't worry too much.