Can CVS do this? Accused of stealing?

So today I was at CVS and I was getting coupons from the stall, (I am twenty and have a fairly large purse) there wasnt any i wanted so I walked down the aisle and then stuffed them in my purse and then my phone beeped two seconds later and so i reached and checked my phone. (I was getting tampons in case) A worker came up to me today and said I saw you touch something and maybe steal something on the shelf, and there are no shopping bags allowed in the store. I replied that its my purse and not a shopping bag, and his response was like you will have to keep it behind the counter and I took out my wallet and went to get my tampons but put my purse behind the counter and they probably went through it to make sure i didnt steal anything. I didnt touch the shelf at all, and was wondering if this man can legally tell me to keep my purse behind the counter or if it really is cvs company policy that I cant keep my purse with me?