If it was relieved by some stretching and twisting etc, probably there was some residual tension in the muscle fibres. This can happen if you are stressed or do a repetitive action for a long time. I noticed it when I was doing a lot of night driving when I was tired, ended up gripping the wheel when it only needed to be held securely. The tension remains after the action is over, like a kind of tetanus. Then when you need to do something with a slightly different deployment of muscle it causes trembling. The stretching and twisting relaxes the tense muscle fibres and re-sets them so you can use them in another way.

In terms of diet, potassium and calcium are necessary for good nerves and muscle control, so have a banana milk-shake for breakfast for a few days and see if that make a difference.