If the scratching is constant, then yes it needs treatment. If just occasional, then pigs do this.
Likelihood is mange (mites) or lice. Don't panic, mites and lice are easily treated
If lice you can see then as small black dots typically near the ears or in them.
If mites, you can scrape some skin hear the neck and look at under a microscope or get you vet to look at it. Scraping skin is quite easy, just use the back of a knife (not cutting yourself!), or edge of a piece of ply or similar, scrape some skin into your hand and put into a sealed plastic box (old butter tub etc.) and take to your vet.
If either present, then injection if you are happy to do so or get vet to do it, or vet may prescibe a pour on.
You will then need to clean all their bedding (burn if possible) and disinfect their sleeping quarters (hyperox, Virkon or similar stong disinfectant).