This question has come up before. Unfortunately the answer is not clear-cut. PN can be a disability, but is not always; it depends on how it affects your daily life and ability to function/work.

To have a determination made involves a process. If your employer is large enough to have an HR dept/person, you might ask there, or ask your doctor to get the ball rolling.

Folks in the Social Security Disability forum may have some information, as some may have gone through this step at some point.

Doc