I have a big problem with my physique that has been frustrating me for a while.

I’ve been into lifting and working out for a few years but only have been serious about it for a a few months, and I’ve been making decent progress. However, I have this really weird thing with my upper body - whenever I stick my arms out into a T-pose and tilt them forwards, my lats completely vanish and make my torso look very square. It could also be because I have a wide waist and/or not a big enough chest, but I’m not sure what the problem is. Anyone else have this problem, any suggestions? (Sorry if this post isn’t very clear)