I've been doing a lot of research on djinn and have come across many stories like yours that involve a kind of djinn that come to people as they sleep and paralyze them, often appearing to sit on the chest or hold the legs down. It usually is seen as a black mass, if it's seen at all, and will give the person a sense of panic and helplessness, followed by dread. There are other details, as you said in reply to one of the other comments... The name of this particular kind of djinn is called yathoum. As far as I have found in my research this kind of thing inflicts the pure of heart just as easily as the wicked. Djinn have free will, just as humans do, and often, their actions are no more rational than a humans and may not follow with reason. There has been some correlation between conflict in the home and the appearance of this djinn, so you might want to look into that possibility. It might not be you specifically that has the issue, but if it exists in the home and you are already sensitive to them, this may leave you vulnerable. I hope this information was helpful, and just remember, during Ramadan you will find respite from this and may have time to re-evaluate the situations that might be bringing this forward. Djinn are not something to be feared, but certainly should be taken seriosuly when they interfere in our lives. God Bless.