A "cousin" of mine, she was about 4 or 5 I think had chronic pain in her arm. So for quite some time her and her parents went to doctors and specialists all over the place to see if they could cure it. After many attempts and check ups nobody could find anything but every night when she had gone to bed she would get these pains.
After quite some time the conclusion was made that it had something to do with her surroundings, her room/house. And again test were made to she if it was some kind of allergy or something. Again the results showed nothing till someone proposed, after having tried everything else, to get a medium in to see if there was something "other worldly" in the house that was causing the problems. More likely with the person in question being a child and more open to those imputs.
So they had a medium come round and check out the house. What he/she found was a ghost of a man who was looking for his mother. The house had previously been owned by the mother before this family had moved in. The ghost, looking for anwsers had been pinching the young girls arm to get an anwser/attention. So the medium communicated with the ghost to say that his mother no longer lived there and the "pain" in the arm went away.
This medium session was done when the child was somewhere else to not scare her so she also didnt know about it.
I was told that story when I was 16 when we were visiting the family and for some reason that story came up. I have no reason to think they were lying or that there was any reason for it. Im sceptical, as its my nature and because I dont believe in the afterlife. But it makes you wonder.....
The theory Ive always had was based on, I think is superstring theory, which proposes that there are multiple dimension (10 dimension of space and one for time) which are "sheets" in space floating. They ripple like a sheet on water if you will and sometimes these ripples would overlap with the other dimensions. Connecting them and allowing elements to become visible between the two. Which allows for the common example that "ghosts" are always doing mundane, daily things; like sitting in a chair, walking to another room, etc. Within the framework of what I believe in that fits in very well and also explains the "ghosts" without it being religious and "of god".