Your symptoms are entirely consistant with referred pain from the upper thoracic and lower cervical spine. Wikipedia reference-linkFacet joint irritations derived from a spinal protective response. It is not useful to consider your spine to be uninvolved on the basis of either "feel", or active movement tests. Neither is it unusual to have referred events without complaining of similar local spinal joint pain.
The prospect of your ribs somehow developing pain discrete to themselves with no trauma is close to nil, presuming no abherent growths or tumors. Similar likelihood of rib displacement anteriorly , and even if found to be so , is more likely an univolved artifact or antalgic response.
A pair of trained hands will quickly discern the responses to movement at the upper thoracic facet joints, which are very likely to exhibit resistance to and tenderness with passive movements. If those hands are also skilled at mobilisation , you will find a ready and long term solution to your problem.
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