Whats the cause for not being able to sleep?

Treatment of insomian:
 Sleeping on a regular schedule , and exercising regularly , avoiding caffeine intake , and avoiding stress , and you can use sleeping pills that are benzodiazepines its a group of central nervous system depressants, which slow down the nervous system
Diagnosis
by taking full medical history and doing clinical examination , and doing CBC to detect the infection , and test the hormne of thyroid gland TSH , and doing brain MRI 
causes

• Stress
• inflammation
• caffeine intake
• some drugs
• headache
• life style
• allergic reaction

Advice 
you should go to the neurologist to detct the cause and get proper managment