Why would a coworker touch me this much?

So I (f) have this coworker (m) that has been very touchy lately.

he’ll come up to me and say hi and put his hand on my back a few times he’s rubbed my back with the palm of his hand. Or we’ll be talking and he’ll apologize because I didn’t hear him and he’ll put his hands on my back and my shoulder at the same time.

One the strap of my shirt was kinda twisted so started to fix without asking if it was ok to touch or even letting me fix it myself.

He’s also touched my hair before saying I like your hair and then grabbing a piece of it. he’s touched the front of shoulder and the back of my shoulder also the upper and middles of my back.

what would be the reason for all this touching
Why would a coworker touch me this much?
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