I have a dark itchy mole on my back should i be worried?

Not necessarily : A mole can become itchy due to irritation but if it has changed in character it should be examined by an expert.

Need evaluation : The abcde criteria may help here. Check asymmetry, border irregularity, color variation, diameter bigger than a pencil eraser, and evolution/change. The more atypical findings, the more concerning. Dark moles are always worth checking.