Why would my 2 year old be losing her hair and ping out?

My 2 year old daughter has been ping out she has done it 3 times in one day, the doctor tells me this is normal she is also losing alot of her hair in the back the doctor said she is pulling it out when she twirls it from stress from her daddy deploying which may be true but i have never seen her pull it out and when she twirls it, its always on the top not in the back. My mother in law doesnt think this is right i was just wondering if anyone else has experienced this with their child?!