Gads,
To my surprise a few months back, at the time I was checking out the BC30, I noted some feedback about Bast Core racs and arm issues (yes, despite that uber-low flex.) What's your take on this? Are you sure the BC20 hasn't contributed to your pains?
I've wondered about that, but, two things:
A) I think everyone who's had arm issues with the BCs, it's been an elbow issue. And that is definitely something I watch out for, because I eventually got some TE back when I was hitting solely with the BC20 like a madman back in my initial two-month honeymoon phase with the stick. Not so much that I had to stop playing, but I did feel it and had to go with an elbow strap for a week or two for it to settle down, plus play a bit less.
B) Conversely, my gut tells me the 20 is pretty kind to the shoulder. I started to feel the shoulder pain on a day when I wasn't swinging the 20 and it was like my No. 2 or 3 tester. And when the pain did arrive last, it was always the 20 that the shoulder seemed to feel best with.
Now, since my beloved PKs are tops in the biz for arm issues (well, maybe second to the Exo Tour), I'm thinking of also put an arm-friendly fresh string job of full gut or gut/syngut in my remaining PK 7G to have in the bag as well, along with the 20 and the Prestige. The Prestige is actually the frame I'm most sort of hesitant with at the moment, since that's the frame I was playing with the most when the shoulder pain came. So... not anxious to pick the Prestige up again until I know for sure I'm out of the woods.
In the end, I don't think it was any frame that did it - just overplaying and also overdoing the 'overemphasis' on the new swing, higher arm slot, etc., which put stress on my shoulder that it wasn't used to getting.