Can I add my business in Google Maps without add it on Google+? I have a Google+ page for my website of this shop and I don't want a second Google+ page for the real store. Is possible?
Since you don't want to treat the physical store as a separate business, simply add its address (and other information) to the existing page. Log in to Google+, go to your business page, edit it, save. Then go to http://google.com/business and it should be on the map.