I was recently diagnosed with Myasthenia Gravis in Sept. Neuro doc has me on Mestinon to treat symptoms. Most symptoms have abated to where I can tolerate them easily. However, I am continuing to have a neck/head instability problem that seems to be worsening. Is this a common symptom and if so, will it eventually go away. It only effects me when standing or walking but not when sitting or lying down. Please, any suggestions.