Myositis. This can also be a problem where there is inflammation of the muscles around the eye. If it is bothering you or severe you should go to your ophthalmologist and obtain an ultrasound or a ct scan.
Rolling eye pain. This can be quite normal. If however you do develop pain or discomfort under ordinary eye usage then see your doctor for an examination.
Optic neuritis. Myositis is certainly possible. However, if you are having pain with eye movement associated with fairly severe vision loss, optic neuritis needs to be ruled out as well.