What causes difficulty in falling asleep?

Many people have the situation that they have difficulty falling asleep at night, which is actually a symptom of insomnia. When it's time to sleep, they can't fall asleep when lying in bed, and toss and turn, which makes them feel painful. It is actually the performance of early insomnia. What are the reasons that cause people to have difficulty falling asleep? Only by finding out the reasons can we eradicate the problem. Said expert Meng Xiangjian of Taiyuan Central Asia Traditional Chinese Medicine Hospital.