Hi Bool,
Sorry to hear your story. I started 19 years ago with exactly what you described which turned out to be PD. I started walking with smaller steps, pressing my left arm into my body. My wife thought I had had a small stroke. If I got stressed, my left arm and leg trembled. This would happen while driving if someone cut me up. Dragging my left foot was another early symptom.
PD often starts on one side, mine started on the left hand side, then gradually spread to the rest of the body I can only reinforce what Lindy and the others have said, to get it checked, but unfortunately it does sound like PD. Another useful test is to look for signs of cogwheel rigidity, where the doc will wind your arm around and try to detect an intermittant resistance. Keep in touch with this forum, it is an excellent way of getting comparison with other sufferers.
Best wishes
Ron