UV Unwrapping is eneven I am trying to unwrap a object (shirt) in the blender by marking seams. I added new uv grid image using image texture node.  But for some reason the pattern on unwrapped image is not even on both side. I don't have much experience when it comes to uv unwrpping so I'm not able to figure out what the problem is .I am attaching .blend file, hope that helps.
Thanks in advance.
https://drive.google.com/file/d/1hUIulFz6sgqSMBpHU_EF_8sDqgf0X2nY/view?usp=sharing
Inside the shirt, there is a Ngon that breaks the flow of the edge loops, so your vertical Seam fails to &quot;cut&quot; the model in two halves :

A quick fix would be to add a Seam along on side of this Ngon :

It would also be a good idea to add a Seam inside the arm, same position as outside :

For your future models, i would suggest avoiding unnecessary NGons. Also, you can use the Solidify modifier instead of modelling the outside and the inside, it's much easier and avoid this kind of traps.