Charles H Bosomworth Sleep Paralysis is a normal in as much as the body freezes itself during dream-sleep in order to prevent you from acting out your dreams.
Sometimes this goes awry.
One example is waking but finding yourself unable to move.

That's the biology behind the paralysis. But there is a spiritual component, as the experience is often location specific eg a haunted house, in other words random people who don't experience sleep issues, unknowingly, experience this kind of "dream"

Common experiences are a weight on the chest, being pinned, and even being throttled; hands around the neck.

It appears the presence of a outside force is the cause of the waking-sleep, at our around just before the dawn, which is the usual low point in the bodies rhythm.

Besides an aggressive haunting, the main cause is an encounter with persons and or things which have a demonic connection, this is especially true for Christians, as like moths to a flame demons can follow you home - seeking you out, think of it as like the demons in the Gospels who are compelled to cry out to Jesus - declaring him as God the Son of God.

The other dimension to this is that demons will usually target the youngest, or functionally/emotionally the youngest person in any given group, this pattern is seen in spiritualism, such as when folks "play" with a Ouija board.

Lastly anyone wrestling themselves out of demonic influence, in whatever form that might take, from addiction to a pagan religion, can experience this kind of attack.

Remember the enemy doesn't expend resources if there is no threat.

In conclusion the solution. That's the power in name of Jesus and authority vested in believers through the blood of Jesus Christ.

Rebuke the demon, command it to leave and go to the place God prepared for it from the world's foundation.
Ask the Holy Spirit to intercede and fill the void left by the entity.
This last part is crucial.
Never exorcise any place or person until you may, and they confess Jesus, because without the active presence of the Holy Spirit you can make the situation worse.

Charles H Bosomworth To dig a little deeper, we have to let go of traditional mythology.
Angel means messenger in the bible, literally, the Hebrew word for messenger is Malak, and the Greek word for messenger is Angelos, (from where English derives Angel) in other words "angel" is a invented word that the translators insert into the bible when the context appears to justify it.
Demons are a specific kind of messenger/angel.

But not all messengers are from God or are of God's heaven.
Yes, there is more than one heaven, in fact the bible speaks of three heavens.
2Co 12:2 I knew a man in Christ above fourteen years ago, (whether in the body, I cannot tell; or whether out of the body, I cannot tell: God knoweth;) such an one caught up to the third heaven.

The first heaven is essentially the sky and space beyond that, the physical realm, the second heaven is effectively what people might call the spiritual realm.
It is the second heaven where spiritual warfare takes place.
This is not the third heaven, the Highest heaven of God.

God is of course present, being omnipresent ie existent everywhere, as God says.
Jer 23:23 Am I a God at hand, saith the LORD, and not a God afar off?
Jer 23:24 Can any hide himself in secret places that I shall not see him? saith the LORD. Do not I fill heaven and earth? saith the LORD.

But just as in the Earth, which God fills, the three dimensional world in space that we perceive with our natural senses, there is conflict so the same is true of the second heaven, an largely invisible dimension, which God also transcends.
Eph 6:12 For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places.

Things we see happening in the earth have a counterpart in the second heavenly realm, nations are represented by Princes; Dan 10:20 Then said he, Knowest thou wherefore I come unto thee? and now will I return to fight with the prince of Persia: and when I am gone forth, lo, the prince of Grecia shall come.

At certain times messenger-spiritual-beings, (not spirits in the sense we are spirits, children of the Father of spirits, made in God's image, and God is Spirit cf John 4:24) can leave the second heaven, ie Jud 1:6 And the angels which kept not their first estate,...

Mythology confuses these messengers with God's messengers, but that is category error, not all messengers are of God or from God.
Some messengers leave their first estate - the second heaven in order to sin.
The Prophet Micaiah had a vision where he saw this;
1Ki 22:20 And the LORD said, Who shall persuade Ahab, that he may go up and fall at Ramothgilead? And one said on this manner, and another said on that manner.
1Ki 22:21 And there came forth a spirit, and stood before the LORD, and said, I will persuade him.
1Ki 22:22 And the LORD said unto him, Wherewith? And he said, I will go forth, and I will be a lying spirit in the mouth of all his prophets. And he said, Thou shalt persuade him, and prevail also: go forth, and do so.

In this vision God is seated on his Throne, ie God is all powerful, God then permits this demon to leave the second heaven and become a lying spirit in the mouth of false prophets - because God is omnipotent, nothing that happens, happens without God permitting that.

In order for this to happen however there first has to be sin in action, Ahab will fall because of what Ahab has done, the Prophets will receive a lying spirit because *they* want to lie.
Jer 5:31 "The prophets prophesy falsely, the priests rule by their own authority, and my people love it this way. But what will you do in the end? (ISV)

In short we choose by our actions, words of thought, speech and deed, to lend our God given authority, our dominion in the the earth to demons - remember even Satan had to ask God's permission to strike at Job, and Job said Job 3:25 For the thing which I greatly feared is come upon me, and that which I was afraid of is come unto me.

There is only one Power in heaven and Earth, God, and to man God has given Dominion.
Neither Satan nor his angels, have any power in and of themselves, they only power is given to them by sin in and of man, in whom God has permitted dominion.
Eze 14:4 Therefore speak unto them, and say unto them, Thus saith the Lord GOD; Every man of the house of Israel that setteth up his idols in his heart, and putteth the stumblingblock of his iniquity before his face, and cometh to the prophet; I the LORD will answer him that cometh according to the multitude of his idols;

Remember; we are able to set up idols in our heart.

1Co 10:19 What say I then? that the idol is any thing, or that which is offered in sacrifice to idols is any thing?
1Co 10:20 But I say, that the things which the Gentiles sacrifice, they sacrifice to devils, and not to God: and I would not that ye should have fellowship with devils.
1Co 10:21 Ye cannot drink the cup of the Lord, and the cup of devils: ye cannot be partakers of the Lord's table, and of the table of devils.
1Co 10:22 Do we provoke the Lord to jealousy? are we stronger than he?