No in the vast majority of my experience this is not the case. You should get a chest x-ray as one of the sternal wires may have broken early and not allowed the bones to fuse. Not much that can be done now. But you should see a physician because indolent infections can present this same way, and can also be reasons for re operation.
I have had two OHS in four years and my chest never popped or crackled after either. Both my surgeries were open sternum.