Six hours ago I opened a jar and a half hour later, my right thumb started to move involuntarily from side to side. It stops, then starts all over again, sometimes very fast and other times a bit slower but still a few times a second. Since I had trouble with the jar, I am hoping it's from that and nothing serious. I am 53, female and in otherwise good health. Has anyone else had this? Does anyone know what causes it? Thank you.