at 09:22 AM
Unfortunately I was unable to open the photo to view. I am thinking you wanted that really tight fit that is so popular in a fashion look jacket. While this jacket is already a slim fitting jacket, purchasing a smaller size based on your measurements can cause stress, especially in the shoulder/sleeve area. Since you are in Europe I can only suggest to take the jacket to a leather repair shop to have the seam repaired.
at 11:33 AM
Thank you for answering. I'm attaching photo. But I think you know where it happened and yes I went for a slim fit, not the tightest possible but quite fit. And there is a stress on jacket especially when I rise hands higher. I was just wondering about fixing. Do you recommend going under lining or try to fix it from the outside. I'm a little concerned about anyone touching my jacket :)
at 08:14 AM
It appears the stitching is at the bi-swing, not sure if it is a top stitch or would need to repair from the inside of the jacket. I am not sure where you are located, I do know of a tailor in the UK, et me know if that would help you. Going forward putting stress on any stitching can cause the problem again with the stitching opening up and sometime even causes the leather to tear.