Figured out the problem. Each bone has its own weight paint but is going to affect other bones if they are connected together(*). So the breast should be red. But the mid-torso should gradually turn blue as the breast weight has already been assigned with the breast bone
the point where it should have the most bend which in this case is the mid-torso. I will paint it with a higher-weight paint. But as it reaches the breast area. It should decrease. The same goes for the upper torso. The top area is where it should have the heavier-weight paint. But slowly decreases as the middle bone has its own weight assigned and you need to have an evenly distributed weight paint for the mesh to work properly
(red means that part will follow the bone 100%, and Blue means not follow)
All the bones have to be properly painted in order for the model to move correctly(*).
thirdly. As I said above. All bones have to be painted correctly in order for the mesh to work correctly(*). This is due to the fact that each bone that's linked to the main bone that you're moving will also move together(Or the fact that the mesh is one piece). causing some of it to distort. You have to check each bone and paint them correspondingly so it works right.
simplified version: paint each part of the body's bone from bottom to top or top to bottom. Paint each bone with its own weight. Same for the next bone. Paint the part where you think will bend the most with the heavier weights. and decrease gradually. And make sure each bone after weight painting has a smooth gradient of the paint
or during painting, you can also check if it's smooth so you don't have to go back and check it later on.
If anything that I pointed out is wrong please let me know I will change it as quickly as possible :D I'll continue to change if I find anything wrong also. Or if I discover it during this weight painting nightmare.
[* meaning I'm not sure about the effect of weight distribution is with bone or mesh]
(Also if want images I can upload but I got a bit lazy:l)