I have constant involuntary movement on my eye, is that normal? Left eye... all day since last 3m

Eye or eyelid? Involuntary twitching of the eyelids is called blepharospasm. Sometimes a segment of the lower eyelids twitch, which is called orbicularis myokymia. In young people, this is common, often associated with sleep deprivation and/or caffeine use. Involuntary movement of the eyeball(s) is called nystagmus or nystagmus-like movement and is often more serious. See your eye doctor to evaluate this.