Pain in my left hand, what can it be?

Just out of know where a few days ago on the top of my left hand, mainly around my pinkie and ring finger bones I developed a pain. At first the sensation was a little numb and felt like my knuckles or hand just needed to popped for relief but nothing would happen. So the pain got worse and now the pain really hurts now when I gently squeeze my hand or mage the top of my left hand between the bones of my ring and pinkie finger below the knuckle area. What can this pain be? It also hurts when I grab my car door to open it, or just any door handles really. I've iced it for a couple of days, and also i've used icey hot and wrapped my hand when I go to bed.