You've had lots of help, and it's all good advice, but I'm going to toss this out:
The rear wheel should not spin freely. It's attached to the rear sprocket, attached to the chain, attached to the forward sprocket, attached to the transmission. And so on.
If it actually spun freely, I'd be scared. The fact that it doesn't is OK. All that stuff is going to cause some drag, even in neutral. There's also going to be some drag from the brake pads. They're designed that way.
If you were to remove the chain and brakes from the rear wheel, and then spin it? If it grinds, you've got an issue. Time for new bearings or maybe just a lube.
With that stuff attached, though there's no way it can spin freely.
The rear wheel should not spin freely. It's attached to the rear sprocket, attached to the chain, attached to the forward sprocket, attached to the transmission. And so on.
If it actually spun freely, I'd be scared. The fact that it doesn't is OK. All that stuff is going to cause some drag, even in neutral. There's also going to be some drag from the brake pads. They're designed that way.
If you were to remove the chain and brakes from the rear wheel, and then spin it? If it grinds, you've got an issue. Time for new bearings or maybe just a lube.
With that stuff attached, though there's no way it can spin freely.