Was at work & grabbed a heavy box, felt a pull in my wrist & could barely move it, a few weeks later it still hurts & pain is up the side of my arm?

MRI : Sounds like a soft tissue injury, perhaps a sprain of the TFCC (triangular cartilage complex) or lateral epicondylitis of the elbow (worsened by wrist movement). If it’s been weeks, I’d recommend seeing a board certified orthopedic hand specialist or sports medicine doc or even occupational Med doc. Ice, anti-inflammatories, and therapy may also help. If not, an MRI may be needed.