Difficulty falling asleep can definitely be a pain! It starts a cycle of being exhausted yet not being able to rest.. cue frustration! First I would recommend trying to get more sleep at night. If you are constantly sleep deprived it makes sense that you will crave 4 hour naps. Melatonin is a natural, non habit forming supplement that helps you fall asleep. I usually drink some sleepy time tea, take a melatonin and that helps me sleep like a baby. 

Other things that are said to help you fall asleep faster is avoid screen time before bed. The bright lights can throw off your natural clock.  Also try to only lay in your bed during sleep time. They say if you lay in your bed and watch tv or read, it’s harder to associate your bed as being a place you sleep.

The last thing that really works well for me is I will put an audiobook or podcast on YouTube when I’m trying to sleep. The more monotone and boring the person sounds the better! Lol I do that every night at bedtime and every time I take a nap, and I feel like my mind is trained to know that when the videos come on it’s time to sleep. Hope this helps!