It does sound like it was a contact with a spirit and how they passed away. As a medium it is something that happens quite often in various ways, they just like to tell you how they passed over. You can clear it very quickly by grounding or asking them to back off a bit.

As far as Kundalini is concerned, Iv heard of it but never related to Mediumship. Its something that usually doesnt go hand in hand as its an Eastern philosophy where Mediumship originated in America and thus follows a Western philosophy.