If lactose intolerance is suspected, your doctor can arrange a diagnostic test for lactase activity. You will have to learn to recognize and avoid lactose-containing foods. The symptoms of primary lactose intolerance usually first appear in older children and adults. Those with primary lactose intolerance seem to be unable to digest the sugar in milk properly. It gradually disappears when you get over the illness.
Milk chocolate is exactly that chocolate made with milk.
Bars and chocolate chips of semi-sweet or bittersweet chocolate are normally made without milk, and so are many candy bars that contain only dark chocolate. Some candy bars do contain milk fat, but that should not be a problem. Check ingredients lists to be sure. And lots of sour ball, gummy bear and similar non-chocolate candy should be fine. For example, try half a glass instead of a full glass.