I hear you all, and i see the tennis-elbow and cortisone....
here a little story about my dad 15 years ago
Diagnosed tennis elbow after having a returning pain in his arm. (also more work, more pain etc etc) Things got worse and more frequent and the cortisone treatments started.
Weekly injections for 4 months with NO result (except for the side effects). Doctors started talking about operation.
My dad's no big fan of knives and needles so goes to a chiropracter following the advise of a friend.
1, ONE treatment and his whole tennis-elbow thing was solved. instantly.
Nerves run to your spine, one of his discs was slightly out of place and putting pressure on the nerves related to his arm. As simple as that.
Pain is a perception and the cause can be anywhere down the line. Think of it as an electric line with a lamp at the end, when the light goes out it does not mean the bulb went out also the cable can be broken.
Be cautious with straightforward diagnoses which are solved by masking treatments (as cortisones, painskillers, etc).