What does it mean when a 50 year old has a problem with slight jumping or shaking for no reason?

Answer 1

Might be Huntington's Chorea or other neurological problem, other medical condition is streptococcal pregnancy (if she fortunate enough). However difficult to answer on the net unless the patient is examined e.g in case of Mitral Stenosis one can experience these types of symptoms.
Consult your physician.

Answer 2

It could mean a lot of things. Could be side effects from heart or BP medications or it could be a medical issue.

See a doctor, please, and good luck to you.