Very sharp pain top of hand (metacarpal area closer to wrist between thumb and pointer) -drop things. no known injury-visible symptoms. comes and gos?

Nonspecific: One cannot diagnose the problem without a thorough examination of your hand and wrist. Possibilities include nerve impingement, spurs, ligament or tendon abnormalities. The fact that the discomfort is not constant indicates a positional effect on one of the above structures. A hand surgeon is best qualified to evaluate and advise you.

Scaphoid : You may have damaged your scaphoid unknowingly. See your doctor and get a definitive diagnosis