Hi Nick and welcome
you may want to do some research on tics induced by photosensitivity

Many people with these kinds of tics find that using LCD screens instead of CRT helps and also always having daylight lamp on so room is never dark with flashing light. Most computer screens are LCD so not sure if yours is

photosensitive induced tics can also be triggered by fluorescent lights etc

From what you describe, it sounds almost like you are having tremors rather than tics, and again different things can be the cause of these

I hope you will discuss this with your parents so they can maybe have some tests run for you