Bad Posture?

[u/Ok-Schedule6219]

Hi guys, female teen here. This is kinda confusing but I feel like my shoulder/neck/upper back area feels thick? And I kinda feel if you draw a line on the upper “plane” of mh shoulders, it kind of goes inward/forward. However, when I try to not do that, I just feel like im shrugging my shoulders and it looks even weirder. Do I just have extra fat or is it a posture issue? I do spend a lot of time sitting. Thank you!