Hello and hope you are doing well.
Inability to sleep could be problems with initiating sleep or maintaining sleep is called insomnia. Problems with breathing (Obstructive sleep apnea), certain medications, restless leg movements and sleep walking/talking could contribute to insomnia. Follow good sleep hygiene measures like going to bed at the same time, waking up at the same time, avoidance of alcohol, smoking and caffeinated beverages. Please consult your primary care physician if problem persists.
Hope this helped and do keep us posted.
There can be many causes for sleep problems- traumatic events, stress, hormonal issues, cycle problems, etc. Some things that really helped me fall into a better sleep was to exercise more during the day, keep a strict bed time and regular eating habits, avoid caffeine after 11am, avoid any media 1/2 hour before sleep, avoid any "stressful" media (anything violent, vivid, thrilling or that has tense moments) 2 hours before sleeping, avoid anything "scary" or "bloody" all together (I got nightmares from the movie Jurassic park and the book Dracula for WEEKS- and no I wasn't under the age of 10, I was 20). I also use mediation techniques to help manage my stress and anxiety.
Hopefully that can give you a little bit of insight/ guidance to what you may need to do.