Thanks for your query. Shivering of hands specific to examinations in absence of any positive findings on investigations could be related to anxiety disorders like specific phobias. Hence, i would suggest a thorough psychiatric evaluation. Psychotherapy
techniques like ERP/ exposure and response prevention may be ideal for treatment. Anti-anxiety medication
like SSRIs as well as beta-blockers might be helpful. Yoga
and breathing relaxation exercises are likely to be beneficial in your case. Wish you good health.