Uncomfortable around someone at work

Someone i'm working with makes me feel terribly uncomfortable, to the point that i dread going in if they're going to be there. They aren't mean or anything, quite the opposite. They're quite complimentary towards me. What makes me feel uncomfortable is the compliments they give me, and that they try to touch/get close to me. I'd be working on something and they'd come up behind me really close, and grab my hand or stroke my arm, and say 'i just wanted to touch your hand/be close to you'. I know that they do it to a few other girls who work there too, and it makes them feel uncomfortable. Is it unreasonable of me to feel uncomfortable, they're quite a bit older than me and it comes off as creepy.

Should i tell a manager about how it's making me feel? On friday they came up behind me and started stroking my back, it's incredibly offputting. Thing is, recently someone else was fired because apparently they were making girls feel uncomfortable (although i had no problem with them), and im worried that if i tell someone people would just think i'm grassing up a decent person. I do know though that they make other women feel uneasy in their presence, and often when they're in the staff room with him, they'd leave if it meant being alone with him.

Am i overreacting? I've never been in this situation before, but surely caressing someone's hand/back at work is innappropriate? Im worried that if i tell someone and nothing is done he'll know it was me who told others too.

What do i do?

Who knows? If there is no one near, how can we know?