There had always been a bit of a bump - a wing - as the sleeve neared the shoulder seam.
With that little bump bothering me, I found I wasn't wearing 'Green' very often. What good is a sweater on the shelf? The wing, I was sure could be fixed and this morning, I took the plunge. Pinning out the extra fabric from the inside,
Turning the sweater back to the right side, I worked a mattress stitch seam up the sleeve. Beginning about half way up with a narrow seam, widening the seam as I approached the shoulder, then decreasing it sharply again in the last inch or so before the shoulder seam. What a difference.