What is the reason why children develop tics, does it have to do with trauma or neurological damage?

Neither or both. Tics can occur developmentally around seven years old and dissipate by teenage. However, severe motor movement disorders can be caused by panda's, or inherited as a disease such as generalized anxiety disorder, ocd, or phobias. See the following link: http://www.Pedrheumonlinejournal.Org/april/reviewarti.Htm.
Various Reasons. Somtimes kids develop tics for no clear reason. Tics are more likely in children who have other problems related to anxiety and adhd. Also, some neurological problems and injuries can be related to tics. In addition, infections, such as some strep infections, can cuase tics.