I should be about your age. I am 24 years old and have been healthy for 4 years. To tell you the truth, my chest muscles were similar to yours. Let me give you some advice:

1, bird, it's best to go to the gym to sit or lie on your back with dumbbells, so that you can not only exercise your whole chest muscles, but also practice the middle seam, which will make your chest look good (it's best to try birds from different angles)

2, push-ups, buy a push-up rack, very cheap, try push-ups of different difficulties, especially remember to lean forward, so the stimulation is deeper.

3, bench press, oblique push up, four words: chest and shoulders! Be sure to remember.

4, do more anaerobic exercise,

The last and most important thing is perseverance! ! ! !