That's why if you lean against the wall, you don't just fall through it. The wall pushes back on you as hard as you push on it, and you and the wall stay in place. If you throw something, you put more force behind it than just leaning on it, so it pushes back with more force.
Lightning is seen earlier than the thunder because speed of light is more than the speed of sound. Therefore, even though both occurs as same time and place in the sky, lightning is seen earlier.
