I Picked Up A Box Yesterday With My Right Hand

I picked up a box yesterday with my right hand that was roughly the length of mid thumb to mid pinky if my hand was stretched out....as I walked with it I felt a sudden pop or crack that sent a shooting pain from the base of my pinky to the middle of my hand. Today my hand is sore as heck and hurts extremely bad when I grasp and squeeze even a stapler. If I squeeze my hand with my thumb and close my fingers, I feel a grinding or vibration . what could be wrong