You're on a steep learning curve, aren't you Tracey?
In all my years of cat owning and rescuing, and being a member of so many different animal welfare forums I've lost track, I have never ever heard of a chip causing health problems. Never!
The chip is inserted just under the skin. A cat's skin is loose, not like ours, so the chip cannot migrate to the blood stream, or get lodged in anything vital. They do migrate as other have said, but normally to the shoulders or legs or other harmless places. I do wish unknowledgeable people wouldn't fill someone's head with nonsense and scare them.
When you vaccinate, so ask the vet to include the FeLV part, which is optional on top of the usual vaccine. That's Feline Leukaemia, which in cats is actually a virus and it's always deadly. Not point in taking a risk over that to save a few bob.
Don't worry about having so much to learn. This was a primary reason why this website was set up - to get free help from more experienced owners and rescuers.