Sometimes the reason you can't fall asleep is because you used the computer too late at night. The bright light tells your mind that it is daytime. The same with a Kindle or other device like that.
I asked my doctor about the safest over-the-counter product to use if I couldn't sleep and he suggested Benadryl. Usually it works for me, but sometimes not.
I've heard taking a warm bath at bedtime is a bad idea. It heats up the body and you need to be cooler to sleep. Hot chocolate has caffeine in it too that can keep you awake.
Sometimes I'll get up and eat toast and just have a tiny bit of hot chocolate with it. It seems to help me. Some nights, I just can't sleep.