Proscuitto means 'ham' in Italian; the word is derived from the Italian 'to dry out'. The term proscuitto crudo is applied a dry-cured ham, seasoned, cured and air-dried, which needs no cooking....
Basically, a pastry chef cooks pastries. I don't want to be so blunt here. Pastries are food items that are prepared through baking. Cakes, pies and similar dishes would be examples.