My back drivers side wheel is locked in place, it doesn't move even when i'm driving. What is wrong with it? Is it the e-break or could it be something else? And how do I fix it?

The brake may have locked up on you.

You dont say what year it is, or if you have drum brakes or disc brakes on the back. It could be a stuck emergency brake, which could be the cable that has rusted-up. If you have drum brakes, it could be some piece of metal inside the drum (such as the self-adjuster lever) that has broken free and has gotten jammed under a brake shoe, or it could be a stuck wheel cylinder.
The drum will have to come off to do a repair. Normally this would be easy after removing the wheel. But if the thing is stuck, it will be a fight. You can try removing the wheel, and banging 'inward' on the outside of the drum, at the 3 o'clock and 9 o'clock positions. This might loosen up a stuck emergency brake cable or wheel cylinder. They make tools called 'pullers' that can get the drum off. Expensive tool! Or you could remove the grease cap in the center of the hub, remove the retaining nut for the wheel bearings. Then with the wheel bolted onto the lugs, it might be possible to wiggle the tire and work the drum outward and off. And when repairing the drivers side, the brake other side should be dismantled for examination as well.

^^^Why would the year matter?

Only because the older the car the more likely a handbrake cable could be stiff from rust and disuse, and the more likely a wheel cylinder could be sticking from internal corrosion. I dont know if there were years when the 95-99 Neons only had drums in back, or only had discs in back? Mine is a 97 - with drums.

Any year neon can have rear discs, just so you know.

Most Neons have drum brakes in the rear.I have never seen one with rear disc brakes

Most Neons have drum brakes in the rear.I have never seen one with rear disc brakes
All R/T's and ACR's came with rear disc brakes. 95 Sport Coupes also came with rear discs...others did as well.

sounds to me like E-brake locked up or piston all the way out and locked??????