Modern Vespa

I have noticed my rear break on my 2006 Vespa LX50 locks up when I have pressed onto my rear break. I did some tests on it and every time I press down on my rear break, the cable doesn't get loose it just stays very tight which causes horrible noises when trying to move off.
What could this be? Is it as easy as adjusting the cable or is it more in depth?

check your rear brake shoes i dont think you have any left..

Where about on the bike is it located? And is it easy to do myself?

inside the rear hub, you may need a mechanic or youtube.

?si=2o6B_1K8E8gQ0zbz

It seems simple to do from what youtube has said. Is this the biggest chance that it could be? Or could it be anything else?

This is not what ive seen on YouTube, as that one talks about the break pads and not about the brake shoe which is what I have found:

it may or may not where do you live, is there a scooter shop close by?

The pads are on the disk brake on the front wheel, brake shoes are inside the rear wheel hub. The video here shows the brake shoes on the rear wheel.
I think the rear wheel will have to be removed to see what's wrong with the brake.

Exhaust and rear wheel need to be removed to inspect shoes

How many miles on scooter?

Yes it doesn't seem too hard to do.
It has 15,724 miles.

You'll need a set of metric sockets, and though the video doesn't show it you should use a torque wrench to reassemble the wheel and exhaust.

Have you ever inspected the brake shoes on the rear and pads on the front?

I never had, I got the bike last year in July.

So you have done no maintenance on it?

Before I had the bike it wasn't used very much, only once every 2 weeks just so it can keep it going and he never used to put much fuel in it so it didn't get dirty. Ever since I have had it, I have changed the rear and front bulb, replaced the exhaust due to rust, changed and clean the air filter every 3 weeks, changed the starter motor and alternator, cleaning the carb, rear wheel change.

I doubt it's the brake shoes (though it might be) but my chief suspect would be the Bowden cable itself. I bet it's had some moisture in there, and has rusted to the point where it doesn't want move freely. Easily diagnosed, as unhitching the brake cable will be the first step to removing the shoes anyway...