Having hard time fall into sleep and stay in sleep are the symptom of Magnesium deficiency.
Eat more Mg rich food such as spinach, seeds and nuts, dark chocolate, coconut water...(do a search) the only problem is we have to eat a lot of these food every day to get enough required Mg for our body.
The alternatives are taking supplement like Magnesium glycinate or apply Magnesium oil on the skin or taking Magnesium bath with Magnesium chloride.
And large amount of Magnesium can be found in the sea water too, you can soak in sea water to get the free Mg from the natures.