Here's some yoga stretching excerises that might be useful. I even stretch my upper arm and shoulders as well. I recommend using ice too, as it decreases blood flow to the iced area. Ultra-sound could be help too, which a physical therapist will have. This would involve cost though. Lastly, I use a back-brace for added lower back support, and tennis-elbow strap, to take the tension of the tendons around the elbow.
The bass position sounds about right. The method I use is, where the bass is when I'm sitting, is same when I'm standing. So it's always at the same position, whether I'm sitting or standing. Bit of Billy Sheehan methodology there for ya.
All seems very complicated, but keeps me pain free, and allows me to put in a little bit more effort.
Bend hand to the right
Bend hand to the left
Bend hand downward
Bend hand downward but reversed
