How do i break this habit of pulling hairs on the side of my chin? could i have trichotillomania?

Could be: Repetitively pulling hair without being able to stop is a simple definition of trichotillomania - but it may be a simple nervous habit that may respond to behavioral or other interventions. If it is causing infections, problems in functioning, problems with others, etc, certainly seekign a psychological or psychiatric consultation for diagnosis would be appropriate.