So sorry to hear that you are having to deal with cold sores. Unfortunately, once you have the virus, you have it for the rest of your life. For most people it is something that will come and go based on stress levels and other factors, but does not greatly affect quality of life. It is likely that you have had the virus for some time and never had symptoms before.
Alternatively, it is very readily passed from one person to another, either through kissing, sharing utensils, or other contact with a persons saliva. Given that the virus is so prevalent, so infectious, and so easily passed, parent do often share it with their children. Generally, the first encounter with the virus occurs for most people between the ages of 1 and 6 years old. As for treatment, there are many treatments available, and yes, they do help (although they will never remove the virus from your body, and it will likely come back under certain circumstances in the future).
Most of the creams and pills that you can take will reduce the time that you suffer from the sores by about a day or so, and they are most effective when started as soon as you suspect that a cold sore is about to develop. Please see your doctor
if you have other symptoms as well, or if the lesions persist for longer than a few days.