Having a Fit

In dressmaking, a fit is also known as a fitting. I've been attempting to fit myself with the dress I am working on, which for most aspects is okay (but not ideal-Mom usually helps me with fitting issues, but she is away at present!). I only have trouble with back adjustments, hemming and now in the shoulder over which I am just about ready to have a geniune fit, as in hissy. I have no idea what has happened, in the mock-ups the shoulder was never an issue and now all of a sudden I have this diagonal wrinkle indicating stress at the shoulder. I've tried resetting the sleeves. No change. I've since taken out the shoulder seams, but that didn't seem to make a difference either. Now I suspect the collar is creating the strain, which is what I feared and now I dread re-doing. I have clipped the seam allowances to 1/4 inch already, which will make reconstruction a challenge, but I've got to get this right. The wedding is Saturday, and I pretty much lose tomorrow since I'm going with friends to see Coldplay in Virginia. I don't like the other options in my closet, and I'm getting down to the wire here.