hello Sue
social anxiety is the overwhelming fear of being embarrassed, humiliated, judged or evaluated negatively in social situations.
the degree and severity of symptoms is essentially what separates it from shyness. it impairs and interferes with 'normal' life.
it is usually accompanied by physical symptoms and can be extremely debilitating. the visibility of the symptoms alone can create a vicious cycle.
there are two different kinds of social anxiety - generalised which encompasses a wide range of social situations and specific which relates to just one specific kind of social situation.
the onset is usually childhood or adolescence.
it is frequently accompanied by other anxiety and mental disorders.
most people would experience some forms of shyness. the degree to which that shyness is interfering with life would be the strongest indicator as to whether it's shyness or social anxiety at work.