My son is 2 months old and has had tremors in his left hands, it usually comes and go. but today it happened twice in his left hand. i'm just curious and a bit concerned. what could be the course?

Likely normal: What you call tremors are likely just the unrefined "puppy dog" movements we see in early infancy. Their nervous system has not linked up all the muscle control fibers to have smooth movements at that age. Control develops from top down and in to out. You have head control before you walk, can control placement of your hands before controlling fingers. Refined finger control comes in at 6y.