I have scratch looking lines on my back what are they from?!

Every week or twice a week I notice these scratch looking lines on my upper back and shoulders. I know it’s not what food and drinks I intake , I’m lactose and I’m a college athlete so I have a very strict diet. I’ve done so much research but can’t find anything and wanted to look it up before going to the dermatologist.

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is it possible you could be scratching yourself in your sleep?