My shoulder has been sore all day

I woke up this morning with a really sore and stiff left shoulder, the stiffness and pain radiated up into my neck even. Right now, as I am getting ready to shut off the computer and go to sleep, my shoulder still hurts just as much as it did this morning when I got up. :-/

I'm not sure just what it was that I did to the poor thing, possibly it was cause by my helping dad walk and his weight being on it. I'm not sure. Whatever it was, I'm hoping a warm water bottle will help it out.