If my rib starts to shake out of nowhere, should i be worried? like if it vibrated out of the blue

It's not your ribs..: Ribs are made of bone and cartilage, which do not have the ability to move on their own. All bones move because they are attached to muscle and tendons. It is like the intercostal muscles (ones between the ribs) that are 'vibrating' or fasciculating, and the cause is often unknown, sometimes muscle fatigue. Example, this may occur with the eyelid. It will likely go away as mysteriously as it came.