The gear to shift it into drive will not stay and it is possible to Move it back and forth without pressing the button while driving?

So when I am driving my automatic transmission car, I no longer have to brake or press the button when shifting my car's gear. If I slightly push it or pull it, it moves back and forth. These two things also popped up on the screen that say, "Check transmission system" and "Check emissions system" at the same time this started happening. I drive the car listed above LX 2 Door. I don't understand the issue, please help.