Thumb twitching for 3 months and hand pain....please help :)

[worriedhelpme]

In mid August, my left thumb began twitching in the early morning while I was sleeping.  3 months later, it still twitches continuously.  I had a hard time making a fist or bending my thumb.  I have problems opening jars and turn things or even stapling paper since this began.  It stopped twitching for a few hours and has not stopped since. The first month my whole arm was hurting and my fingers were numb.  I had a pins and needles feeling for many days.  

My family doctor sent me to a Neurologist.  The Neurologist sent me to have an MRI of my head and neck.  They came back ok.  They did find an arachnoid cyst which he said was on the wrong side of my head to be affecting my left side and said that it was harmless.  I had Evoke Potential test done for MS which came back fine.  I am to go for an EMG (something like a muscle tap where needles will be put into my arm, not sure what it’s called)

3 months later, now my right hand is beginning to bother me.  It feels as though I have small electrical shocks running through my hand.  I am so worried that I will develop a twitch in my right hand now.  My Neurologist is at a loss and is unsure of what it could be.  I have had no injury and am right handed. You can see the soft fleshy part of my left hand between my thumb and index finger twitching constantly.

Has anyone heard of this?  Will my thumb stop twitching?  It’s driving me nuts giving me a hard time sleeping and carrying on with day to day activities.  If my right hand develops this, I will not be able to function properly. This is how my left hand began three months ago.
Please, can someone offer their expertise? Is this something scary like MS?
Many thanks.