It is very difficult to get good diagnostics of the upper neck. An MRI with the head turned sharply to each side can show instability. Sleeping on ones back without a pillow under the head but instead positioned so the head does not tilt or fall to the side may help. Straight posture is important, especially when relaxed or sleeping. The inflammation that develops from these undiagnosed injuries can cause a myriad of problems. Often, there are no other neck symptoms.