Can you please suggest some food containing protein to have in the morning for gaining weight?

Range of choices: Milk (fat or not), red or white meat or fish, tofu, or protein supplements with whey or soy. Whatever suits your tastes. Your physician or a dietician can advise you. You'll benefit as much or more from getting intensively involved with fitness activities; this will ensure your weight gains include healthy muscle and not just fat. Exercise normalizes your appetite & gives you the body you want.