Mouse Key Bind Issue
Having spent hours trying to solve this problem and dealing with EA's useless automated support, I wanted to add this solution to this database for others pulling their hair out over it.
Problem: When playing Battlefield 4, all the mouse buttons are hard bound to certain actions (left mouse button is fire, middle mouse is change weapon, right mouse button is toggle fire mode, etc). You cannot change these controls in the game and attempting to will just cause pressing those buttons to do the action you want and the hard bound action at the same time.
Solution: You can thank Microsoft because with Windows 10 they included a mouse driver that automatically binds controls for certain games on certain mice (my mouse being one of them, a Rat Pro X). Go into Device Manager in control panel and expand Human Interface Devices. Scroll down and find HID-compliant game controller. Right click on it and hit Disable device and your problem should be solved.
I hope this helps someone else who was as frustrated as I was.
Oh, thanks.