Homeopathic therapies are commonly used by numerous people throughout the country and throughout the world. They work for some and don't work for others. Regardless, insomnia
is a serious condition. I would recommend that you discuss this with your primary care doctor
to have this evaluated and hopefully treated.
Firstly, insomnia is a common condition. There are many different causes that can be treated, often without medicine. For example, many people have caffeine prior to sleep or are exposed to to much light prior to sleep that makes it difficult to sleep. Avoiding these and improving sleep habits can help. I would recommend talking to your doctor as there are many ways to improve your problem. In addition, there are some serious causes of insomnia that should be ruled out.
To answer your broader question, yes homeopathic therapies work some of the time. Some of the time they don't. The fundamental problem with these types of medicines is that they are not studied like others. As such, we can not conclusively say they work, don't work and can't confidently know what the side effects might be. As such, as a medical doctor I do not recommend them.
Talk to your doctor about insomnia as well as any potential new medicine (homeopathic or otherwise) might take.