I'm a pretty new Colemak user, and I'm at ~55-60 WPM after a week of practice. I'm using the full layout (with Backspace on homerow), and I'm starting to feel discomfort on my left pinky as a result of its excessive use (as Backspace, Shift, Q/A/Z/...). I feel fine when I use the original Backspace key instead, but I really dislike having to reach so far. I also normally touch type in QWERTY and haven't felt any discomfort before, so it's most likely the Backspace-on-left-pinky that's the issue.
Has anyone else experienced this? Is this generally something that the fingers just have to adapt to, or is it just too much for one finger?
Colemak (start 11.5.12): ~80 WPM.
QWERTY: ~90 WPM.