Hi and welcome to the Chiari forum,
Have u ever been tested for Ehlers-Danlos? it can cause the all over pain similar to Fibro, and in fact I was mis-Dx'd with fibro....and then told it was the EDS....
EDS can also cause symptoms similar to those prior to ur decompression, so very Chiari like...in that u can have the brain fog, motor skills lacking etc...
EDS is a related condition to Chiari....so I would start there.....
Like Selma, I too was misdiagnosed with fibromyalgia about two years after my first decompression. After my second (more complete decompression) my fibro symptoms disappeared completely.