Sounds like a case of Taffyitis to me - Gogs are not so susceptible due to the typical increase in strength of living and working in mountainous terrain
Seriously, this is often mis diagnosed as HAVS. Obviously, we can't say for sure, and Dee isn't around to grill about it, but we have come across this before (including myself temporarily).
If its what I think it is, you have pressure on the major nerve line running down the shoulders to the fingers. This is probbaly caused by typical Arborist poor posture; hyper extended upper spine, pinching the nerve. This is caused by inefficient, repetitive pulling actions without correction (how many times do you push your bodyweight everyday? Hardly at all is my guess).
I corrected my posture problems over 3 years by Dee's careful attention to my programme, and having me lie on styrofoam tubes in specific ways. This together with specific regular exercise (based on pilates, not running round in circles)reset my spinal components including head, neck, shoulders, the 4 curves of the spine, the pelvic tilt, the tight hamstrings right down to the tight arches in my feet. I keep this in check by watching my posture, and feeling when I'm reverting (like now typing this).
The good news is, you guys are young enough to correct now without degeneration. If you're not young, dumb and full of something sticky, ;-) you'll take good advice and training on keeping a correct posture, and using ergonomic and energy efficient climbing techniques in your daily work. Its not just big trees that need to be climbed with bio-mechanical efficiency, its lots of little ones too! If the boss thinks you're being a big girls blouse, work for someone more interested in regular care & maintenance of their human resources.
Good luck. Dee has another arborist on her books who has been in perpetual rehab with a physio. They just don't understand the job (or care) and don't treat the whole muscular skeletal system. Its like looking at crown dieback, without thinking about the roots and recent site development over the fence!
My advice apart from improved work technique and finding a good remedial personal trainer - build up to 20 or 30 perfect push ups a night. With proper square shoulders, level back (no arse in the air or sagging back!) and slow dsecent to 90 degree arm bend then steady back up without locking the elbows (breathe in down, out up). Don't be surprised if you struggle to do 5 - its the technique not the number that is important. Have some task master watch yo to make sure you're square and not slacking. Don't forget the head is attached to the spine, and so that should be in a line with your spine too (look down without dipping your forehead).
In fact, if you concentrate on getting it right, I'd be surprised if many arbs could do two.
I hope it helps. I know how serious this could be if you continue for another 10 yrs without getting to the bottom of it.
