pulling at side of the bust, under the armholes - is it the armholes or back?

I just made a toile of a shirt I'm planning on making and there's some pulling at the side of the bust. But I can't tell if it's the armhole or the width of my back panel? I thought it was the armhole, but now I'm not sure. Suggestions?

I feel like it can't be the front because there's too much slack in the front, between the breasts, can it be?

Here's a pic:



(posted at needledown.com)

You probably need some shaping at the bust.  It's very difficult to fit curves with straight lines--think of it like putting a piece of fabric over a beach ball--it wouldn't fit very well, but if you add a dart, suddenly things begin to fit much better.  It looks like you need to add length as well over the bust.

I wouldn't mess with the armholes--you can get into big problems quickly with them.  I'd go back to whatever they were before and add a dart.  It looks like your center fronts are matching, so I don't think you need width over the bust, but if your back is feeling tight, you might need to add a little width vertically in the back about mid shoulder (you can ease it back into the shoulder seam or take a dart in the shoulder so the shoulder seams match)...you'll know if you need this if there are pulls around the armscye in your upper back--but mostly it'll feel a bit tight in your upper back.

Thank you, a dart sounds exactly like what I need! I'm going to give it a whirl this weekend and check my back width and bust length too. I wouldn't have thought of my bust length as also being a problem, it feels counter-intuitive at first, but it makes sense. 

I'll report back. 

I just finished making a muslin similar to yours and I had the very same problem.  I decided to go with some gathers under the bust on the bodice front pieces - it worked well.  Just another option, but darts will certainly work well also!

Often when you have curved areas on your body, they will need more fabric to  cover them in length as well as width--that is what's happening when you see women wearing empire lines that cut them mid-bust.

Back to fruit--a grapefruit is not just wider than an orange, it is also taller if that makes sense.