Hi and welcome to the forum....It is possible ur chiari was there, but not reported on.Most radiologists only report on what they are asked to lok for and many consider chiari an incidential finding.So it can be that ur chiari has grown a bit bigger than it was then and is more noticable.
And as Shane mentioned it is a good idea to be checked for a syrinx and tethered cord...all related to chiari.
Please keep us updated on ur progress and ifu have more questions we r here : )
"selma:"
It's possible that you had a triple whammy, but most likely they're related.
Have you been checked for Degenerative Disc Disease or any other nerve disorders? They often show up on Chiari patients. Do you have any syrinx?