I have developed a tremor in my left hand concerned that this is a progression of something that went not diagnosed?

I have developed a tremor in my left hand for the last 5 months. It is only when I do one specific action (i.e chopping movement from the elbow) My hand quivers from side to side when I do this. I also have tenderness in my elbow and my doctor is dismissive of it and says it must be tennis elbow. But it is going on so long now I am getting concerned. I have seen a neurologist 3 years ago in relation to tingling of the arms and legs and jumping muscles. She did some simple neurological exams on me and said it was not anything but maybe fibromyalgia. I am concerned that this is a progression of something that went undiagnosed.