Smooth muscle is mainly distributed in gastrointestinal tract and urinary system, such as urethral sphincter. Smooth muscle is generally not controlled by individual subjective consciousness, but is regulated by autonomic nervous system of viscera and hormones in blood.

Gastric muscle is smooth muscle. It has several remarkable characteristics, that is, muscles contract or relax once for a long time, and some of them reach several seconds or even dozens of seconds. It crawls slowly, shrinking only once for such a long time, slower than a snail; Another feature of it is that it can be expanded, just like candy or rubber, and it can do a lot of stretching. For example, the stomach can hold food several times its original volume.

So it's hard for you to exercise your abdominal muscles. The only way I can think of is to eat as much as possible every time you eat. If you can't stand it, don't eat it, so that your abdominal muscles can be stretched as much as possible and you can get exercise.

But I don't think you're serious.

In short, don't exercise your abdominal muscles.

My stomach is not good. I usually eat 50 grams of raw peanuts with clothes every day, which is very nourishing.

Moreover, the muscles in the chest exert force to cause pain, which has nothing to do with the stomach. That seems to be pectoralis major.