After I jammed my finger it won't move regularly. What is this?

May need an x-ray. Treatment for a jammed finger includes: rest, cold packs, & elevating that hand up to the chest. Motrin or Advil (ibuprofen) for 3 days helps reduce the swelling & pain. One can "buddy splint" by taping the injured finger to the finger next to it for a few days. If the pain is severe, the finger crooked, or the range of motion significantly decreased, a primary or orthopedic doctor can evaluate & do an x-ray.
An injury. That requires seeing a hand surgeon if you want to use it again. Can't be more specific without exam and xrays.