No, it's not from MG. You need to go see an eye doctor or your primary doctor right away. It may be nothing or it could be from a drug or another condition.

http://www.mayoclinic.com/health/sub...nd%2Ddiagnosis

Only a doctor can tell you for sure why it happened.

MG does NOT cause pain in the eyeball itself.

I hope you will see a doctor today.

Annie