Welcome the board Mama4!
Sweety after 20 odd years as a CNA I would say that arm and shoulder is just wore out! I can only imagine the times it has hed more body weight then your own as well as the constant pulling,tugging,and repititive morions taking place not mention the tears shed on it.
Please keep on your Doc and you did not mention if this was a workmans comp Doc or your own but I would make sure I filed a claim with my employer immediately if you have not done so as it is a great possibi;iy this eventually turns out to be work related.
If this Doc doesnt do what you think should be done please find another and if he isnt an Ortho man ask for a referral now not later. I could never get aleve to relieve so much as a headache not to mention the toll it is taking on your tummy so dont let them keep prescribing it to you for long periods of time.
If you have not been using heat please try it as there are times I get as much relief from that as I do anything. Those therma care pads that you stick on and they stay hot for 12 hours are a miracle too! If the heat helps any then you know it isnt in your head thats for sure!
I had two meniscal tear to a knee that were found in surgery that did NOT show on the MRI done 4 days prior and also a bone spur under the knee cap so not everything shows all of the time or if they saw then they didnt put any of them in the MRI report!
Now if all of this fails to bring relief and none of the tests and whatnots show any reason for the pain please ask for a chect x-ray even as far fetched as it sounds many times shoulder and arm pain is caused by something going on int he lungs.
Good luck to you and please keep us posted as to your progress or even lack of it.