Question
I have had pain in my right deltoid for about 8 weeks. This pain is not in the shoulder but feels like the opposite end(Insertion or origin?) mid way down arm between shoulder and elbow. I can only raise my arm out to the side about half way without pretty bad pain in this area. I have had x-rays and mri of shoulder as my GP is adamant this is where the pain is originating as she hears a clicking when my shoulder rotates. MRI shows mild inflammation and mild arthritis. I am 43 and feel this is normal.   I also can not bear any weight on this arm as in a push up or using it to push my weight up when sitting up in bed.  I have no recollection of an injury to this arm just remember it started to hurt when I tried to raise it. It basically doesn't hurt otherwise although sometimes when I have used it and tried to force movement I get a general ache and heaviness in the arm.  I am a Registered Dental Hygienist so am prone to lots of repetitive aches and pans and do struggle with right upper back shoulder neck pain which I get a monthly 1 hour massage to help keep it loose. I still don't see how my work might have affected this area.  Any suggestions?

Answer
In the repetition, you are probably causing an overuse injury to the insertion of the deltoid.  This can cause pain into the upper arm.  Also, being a hygenist, you are in some awkward positions, and may be causing some strain in the neck, putting pressure on a nerve, and you are feeling radiating pain into the arm.  If the MRI was negative, essentially, I would consider seeking a good chiropractor for an examination and treatment.