I am seeing an orthopedist. He did my shoulder surgery in december. The MRI showed I had a torn rotator cuff, but when he got in he couldn't find a tear but extreme fraying of the cuff. He also found and removed a 6 mm bond spur that had grown into the cuff.
You need to see an orthopedist. Take the MRI. Both Radiologists and orthos "read" the films, but for different things. Regular doctors do not "read" films. Since the radiologist didn't find anything wrong, you might want to try going to the Chiropractor for a manipulation.
MRI of my neck was normal. i have developed tennis elbow after physical therapy. My shoulder just doesn't feel quite right and the pain and catching in my shoulder and upper arm is front to inside.
Generally speaking, pain in the thumb and forefinger are caused from nerve damage or pinching in the elbow going into the neck. Since you complain of neck pain also, then have an xray of the neck done. Take the xrays to an orthopedist for evaluation, or to a Chiro for an adjustment.