Hi Doc, I hope everything is well with you. I just...

what is the treatment of insomnia?
the reatmkent of insomia is gradually stated with changing the sleeping habits into better ones by the help of a sleep doctor ( usually a psychiatrist ) then if it didnt work then he might start the treatment with anti histamine drugs such as promethiazine then an spcial drugs for the treatment of insomnia such as ramelteon or in some other cases the treatment with benzodiazepines drug group is the last resort such as alprazolam ( xanax ) 
what are the signs and symptoms of insomnia ?

• morning fatigue 
• many mistakes at the work 
• sleep too late and wake too early 
• being affraid from the night time 
• errors in doing the usual automated work such as when driving a car or writing 

what are the causes of insomnia ?

• your job prescription ( doctor, policeman, pilot e.t.c )
• bad and unhealthy sleeping place ( too much light or too much noise )
• sleeping in a small bed 
• sleeping in a uncomfortable bed  
• any type of screens ( laptops mobile phones or even an electronic wristwatch ) 
• drinking caffienated drinks such as coffee cola or energy drinks 
• eat at night 
• travelling for a different timezones

what are the dagnostic tests ?
the doctor will check you past medical history and exam you clinically then he will let you sleep in a comfortable bed in a special sleep clinic so the doctor can observe you while you are asleep or trying to sleep 
zinc supplement and stress tablets ?
there are many families of stress drugs but in general the zinc doesnt interact with the stress drugs but you should consult your pharmacist prior taking any medication