At first take my he heartiest love. My question is that I can't sleep as well at night. What'a reasons and solutions? Thank you.

Vaied causes. In a young person, the main cause is emotional, either anxiety or depression. You need to tell us what is on your mind which keeps you awake, preventing youn from falling sleep? If you fall sleep ok but wake up later, that is more serious and may need a visit with a doctor and seek medication to help you get good sleep.