Hi and welcome,
"2 weeks ago. They originated in my left leg. I had a burning/tingling pain running down my bottom into my leg all the way to my ankle. Next, the muscle twitches started first in the left leg and then moved throughout the body" is definitely not a suggestive-consistent pattern of a chronic or serious neurological disease like MS or even ALS.
Burning, tingling, pins and needles, pain etc that runs down from your bottom to your ankle is the classic sign of sciatica because it travels the route of the sciatic nerve and to be brutally honest, the fact the muscle twitches have spread so fast throughout your body, it is more likely a physical refection of your escalating level of anxiety, and or caused by a general vitamin imbalance eg magnesium etc
Hypermobility is commonly used by physiotherapists and it just describes excessive movement or flexibility in one or more joints, many people can have hypermobile joints and don't have any problems at all but hypermobile joints are more prone to recurrent injury as the excessive movement can cause musculoskeletal problems and joint pain.....weak muscle tone or strength around the joint also contributes to hypermobility so your physical fitness exercises should be designed to avoid injury to joints...
It's uncommon to unnecessarily cause your self a little anxiety after googling symptoms, but if your talking about ignoring and skipping over all the common and un-scary causes of your symptoms to get to the serious or chronic medical conditions and the reading about those conditions is really freaking you out....stop doing the behaviour's that are feeding the anxiety, stop googling symptoms and sending your self down a dark and scary path!
I hope that helps.......JJ