Thank you for posting your query.
These disturbances are due to changes in autonomic, mainly the sympathetic nervous system
On coughing or with other activities as described by you, there is release of sympatho-mimetic amines, which can cause shaking and eyelid twitches.
There is no need to worry about them.
I hope it helps.
Please get back if you require any additional information.
Dr Sudhir Kumar MD (Internal Medicine), DM (Neurology)
Senior Consultant Neurologist
Apollo Hospitals, Hyderabad,
My personal URL on this website: http://bit.ly/Dr-Sudhir-kumar
My blog: http://bestneurodoctor.blogspot.com/