Hi and welcome to the Chiari forum.
No worries....it is ok to be nervous and scared as it is a major surgery...and the unknown is always scary....but you will be ok.....I had surgery almost 6 yrs ago and I did well.
We do have a thread in the Health Pages for tips for the hospital stay....I will get that link and post it for you...
You will not be able to move to the point of hurting yourself post op...
You will have pain, and you will need to move your neck but the Dr will tell you how to move so it is safe and helpful to your recovery.
Pain levels will vary from person to person....if you can handle pain well you should be ok,,,,you will also be medicated to help with it so that should be ok too....
Make sure to post your surgery date on the list your surgery date so a Prayer Thread is posted for you.
Wishing you all the best <3