There are various types of dreams;
Night Visits
Guidance
Past Life Images
Troubled Mind
Nightmares
You are not a person who has a spirit, but rather a spirit who wears a physical body while on the earth plane as you would wear your clothes. When your earth life is finished you remove these clothes (physical body) and move on to your 'real' home in the spirit world. When the time comes for your next life, you put on a new set of clothes - the new body - which you wear until that death. This however is not the only time you remove your 'clothes' and go home for a visit, you do so every night while the physical body rests. When this happens (sleep) the real you, the spirit you, goes to the spirit world where you visit and speak with those in the spirit world. Sometimes it is with family and friends who have passed on, sometimes it is with guides or helpers, etc.
The brain when waking, because it remained behind on the pillow and did not travel with the spirit body to the spirit world, can only recall the images of these travels as a 'dream'.
Often, while in the spirit world, a meeting is held with guides and helpers where the course of your life is discussed. Here you are shown possible obstacles and hurdles you will encounter and advised on how best to approach these. When you wake you recall these images as dreams.
In much the same way as you today might recall things that happened to you when you were younger, so too sometimes the spirit recalls things that happened in a past life. These images are also categorized as dreams upon waking.
If you go to bed with troubling images or thoughts these are trapped in there for the night and are mulled over and turned about by the brain trying to find a solution for the troubling situation.
Nightmares may be caused by any one of these above. It may be an unfortunate encounter with a bad spirit on the way to the spirit world, or you may be shown some disturbing scene somewhere in your future, or even an image from a past life such as a violent murder, etc., the troubled mind is usually the source of nightmares as human nature tends to blow everything out of proportion.
