Okay, before you start thinking tennis or golfer's elbow or nerve pain or rotator cuff, read my symptoms. The pain is in a very specific area, the top of my left forearm down the center. The type of pain is completely dependent on the movement. If I jar it in some way, such as when opening a window and it suddenly gives or a car door closing and I reach up to stop it, it's a very sharp pain that has radiated down into my fingers. However, like right now just sitting here, my whole arm is aching. I also have a lot of weakness and some pain when I'm trying to lift my arm sideways or behind me. It hurts in my forearm to reach across my chest. I have had a MRI, it's negative except for showing I have what's called military neck. No pinched nerves or any other issues. Been going on for 6 months and the aching pain is getting more frequent. I do have multiple sclerosis but the sharp pain that only happens when I jar my arm in some way is throwing me off and I have not injured it.