I have had muscle spasms while meditating since age I started meditating at age 19. I learned they were called Kriyas a couple of years ago. My spasms can be anywhere, but are mostly in my solar plexus where they can be very powerful. Although I have never had shaking, your article was very informative on this. I am also very familiar with the Panca Koshas, but never thought about how they relate to my meditation, which they clearly do. I have been in the Bliss Body quite a bit recently while meditating, which is nice.
Blessings -- Alan