Vertex Weight Paint Error When I paint a Vertices the opposite one gets painted too, but the vertex painted isn't mirrored either, it is equal in direction. When I paint a red vertex blue, the opposite one goes from blue to red and even makes the painting non equal. I want them to both be the same colour when painted.

Also the new painted vertices get deformed even when the bones are in resting position, this has only recently happened when returning to my project.

-I do not want the vertices to be mirrored when painting.
Keep in mind that in wireframe view, your strokes are applied to all vertecies behind the brush not just the ones on the closest face. You might try rotataing the model, so only what you want to paint will be hit by the brush, or not using wireframe mode (wireframe mode renders edges as dotted white lines). You can use the "Limit Selection to Visible" button at the bottom toolbar of the viewport to change whether or not your strokes apply to verticies behind the first surface you hit.