Hi. I am 20 years old and my middle knuckle on my left hand has been swollen and in pain especially during use now for 3 weeks. No lymes, frac. Nothin?

Not normal. If there truly was no trauma this may be fluid in the joint. Sounds like you should see a Hand Specialist. It is unlikely this represents a generalized disorder ( eg arthritis) but it needs a "look see" Hope this helps Dr Z.