Why do my fingers twitch?

Am I going even more bonkers or is this normal?
I had a mastectomy on the left side in November, apart from pain and discomfort all seemed to be ok, then last Saturday (13th Dec) my fingers on my left hand suddenly started twitching uncontrollably - It looked really weird!
Is this all to do with the nerves ect on that side and will it get better? or will i have to put up with it?
cheers all,
Tillie45