I hear that Chasing Hawk. We are building container beds and our boards are 2x10"x 8' plus all the screwing, carrying, placement, etc.
You may want to see the Dr. sooner than you are thinking. Not to scare you, but most women wait too lng to see Dr. when having heart problems which for us mimicks other pain. Shoulder pain is one of the most frequent complaints.
Knitting and x-stitch can put a strain on your shoulders if you tend to 'lift' your shoulders while stitching. Maybe you
really should just rest.