Hiya,

My oldest son (7) told me this mornng that he woke in the middle of the night and couldn't move his arms etc (basically couldn't move at all)

I used to get this a few years ago - I think it has happened maybe 7 times in my life - where I would wake and and be totally immobile - couldn't move - not even to breathe - it must only have lasted seconds but felt like forever

i read somewhere it is called sleep paralysis and is not harmful but your body waking up too quickly
has anyone had any experience? know what causes it etc?

Strange my son gets it when i did as well - quite a scary experience
lucky