Maybe you mean using a Les Paul will make you feel tired?

If you mean by that, the heavy Les Paul guitar is actually making your shoulder tired because you are carrying it using the strap.

It is okay.

Leather strap can make your shoulder feel comfortable.

No, it is a price to pay to get such a heavy guitar also a guitar that produce heavy tone.

The Les Paul is a heavy guitar, all you can do is just keep playing it (while you standing and carrying it with the strap) until you are get used to the weight. Until then, you will feel it is comfortable for you. Like you cannot carry a 10kg item today, maybe you should try carry it more and maybe tomorrow you can carry it.

I suggest you better play the guitar normally first. Then only think about that.

You too.

Good one.