So I realize I should go to a Dr but I'mma ask here first

So on Saturday I was doing a bunch of shit I shouldn't be doing like lifting heavy things, throwing heavy things, you get the point. But I hurt my arm. I kinda think I just pulled a muscle but I can't straighten my arm and the pain radiates up from about my wrist to my neck. On top of this I can't hold things in my hand, like I can grab things but I can't hold them for any length of time, and moving my hands and fingers certain ways cause the pain to spike. actions like scrolling on a mouse and counting money.

My arm is super stiff as well