Asking for alimony for the first time
If you or your spouse lives in the county where you lived together, you must file for divorce and alimony at the Probate and Family Court in that county.  Otherwise, you can file in the county where you live or where your spouse lives now.  See Where Do I File to find the right court for your county.

Asking to change your alimony
You must file in the same court that granted the alimony. See Changing Your Alimony for more information.