I've had this symptom, too. I don't know what causes it, but I do have MS. I have a lot of other problems with my eyes and vision as well including double vision, past ON, pupillary defect, blurry vision, and jumpy eyes. It's as though my eyes are glued together with allergy crud, but there's nothing there. It doesn't last as long as 5 minutes, but it seems like forever. I used to also have trouble with my eyes crossing in the mornings.
my blood test and emg were negative for M.G. now the doctors say it could be
just muscles weakness. i am taking vit b12 inj. once a week and for my nerves weakness neurobion fort e inj once a week, and also multivitamin tab. i think this treatment has helped me.
I did a quick search on MedHelp. I came up with an older post with a Dr. Rajgopal answering...Of course, there are loads of posts both agreeing and disagreeing with him. He blames it on a condition called Blepharitis.
Here is the page if you want to read through it;
http://www.medhelp.org/posts/Neurology/Cant-open-eyelid-in-the-morning/show/12438