And also while sleeping at night?
I often get sleep paralysis. And I find them pretty scary while I have them. Evey time I have them, almost every time I have them, I fear something bad will happen to me, like I’m dying or something ( which, once I’m out of the sleep paralysis, I see that I’m alright physically).
Thanks for all answers. 
From Wikipedia:
Sleep paralysis is a common condition characterized by transient partial or total paralysis of skeletal muscles and areflexia that occurs upon awakening from sleep or less often while falling asleep. Stimuli such as touch or sound may terminate the episode, which usually has a duration of seconds to minutes. This condition may occur in normal subjects or be associated with narcolepsy, cataplexy, and hypnagogic hallucinations. The pathophysiology of this condition is closely related to the normal hypotonia that occur during REM sleep. When considered to be a disease, isolated sleep paralysis is classified as MeSH D020188.
Physiologically, it is closely related to the paralysis that occurs as a natural part of REM (rapid eye movement) sleep, which is known as REM atonia. Sleep paralysis occurs when the brain awakes from a REM state, but the bodily paralysis persists. This leaves the person fully conscious, but unable to move. In addition, the state may be accompanied by terrifying hallucinations (hypnopompic or hypnagogic) and an acute sense of danger. Sleep paralysis is particularly frightening to the individual due to the vividness of such hallucinations. The hallucinatory element to sleep paralysis makes it even more likely that someone will interpret the experience as a dream, since completely fanciful, or dream-like, objects may appear in the room alongside one’s normal vision. Some scientists have proposed this condition as a theory for alien abductions and ghostly encounters.
The paralysis can last from several seconds to several minutes "after which the individual may experience panic symptoms and the realization that the distorted perceptions were false". When there is an absence of narcolepsy, sleep paralysis is referred to as isolated sleep paralysis (ISP). "ISP appears to be far more common and recurrent among African Americans than among White Americans or Nigerian Blacks", and is often referred to within African American communities as "the witch riding your back"
Sleep paralysis is most often associated with narcolepsy, a neurological condition in which the person has uncontrollable naps. However, there are many people who experience sleep paralysis without having signs of narcolepsy. Sometimes it runs in families. There is no known explanation why some people experience this paralysis. It is not harmful, although most people report feeling very afraid because they do not know what is happening, and within minutes they gradually or abruptly are able to move again; the episode is often terminated by a sound or a touch on the body.
In some cases, when hypnogogic hallucinations are present, people feel that someone is in the room with them, some experience the feeling that someone or something is sitting on their chest and they feel impending death and suffocation. That has been called the “Hag Phenomena” and has been happening to people over the centuries. These things cause people much anxiety and terror, but there is no physical harm.
What else can you tell me about sleep paralysis?
* Some people with disrupted sleep schedules or circadian rhythm disturbances experience sleep paralysis
* A study found that 35% of subjects with isolated sleep paralysis also reported a history of wake panic attacks unrelated to the experience of paralysis
* Sixteen percent of these persons with isolated sleep paralysis met the criteria for panic disorder
How can I stop the sleep paralysis?
In severe cases, where episodes take place at least once a week for 6 months, medication may be used.
You may be able to minimize the episodes by following good sleep hygiene:
* getting enough sleep
* reduce stress
* exercise regularly (but not too close to bedtime)
* keep a regular sleep schedule