Thanks for the query to H.C.M. Forum.
As you stated in your query that at the level of C4-5 & C5-6 posterolateral protrusion is there , but not associated with any compression.
As nerves ( cervical plexus ) get origin from this place and from cervical plexus may nerves as phrenic , brachial arises.
If compression of cervical plexus is there than there develops pain in the supplying area .
Due to this cervical spondylitis
This is an old reports , hence no value.
If you have any disorder than get fresh one.