Some drugs can give you tremors.
(I was in intensive care with a suspected heart attack. Pain was in the middle of my back. Doctor said it was from stones. One student backtracked and asked me did I tell Specialist that, but I said no, it was a process of elimination from a determined specialist.)
I hope to visit UK for a last time next year, with a cruise from there. I'm pleased I travelled overseas annually when I was young, because I'm now happy to travel and cruise in Australia. Just waiting for some decent itinerary choices.