Itching is a skin sensation prompting a desire to scratch. It can be more or less irritating.
A physical itch can appear when you want something but you won't let yourself have it. You believe someone is in your way or life circumstances make it impossible for you to fulfill your desire. This preoccupies and exasperates you.
Pay attention to what part of your body is itchy and what that part is used for. The location of the itch will have a direct metaphysical correlation. As the skin is representative of the outer self, or personality, you may be afraid of what people might think of you if you take what you want. Or maybe you're afraid of hurting someone's feelings.
Make sure that what you're itching to do is not simply a whim and that it's something you desperately want. If it's just a whim, let go without wanting to control everything and put it off for a while. If you really want this, identify your fears and take action to face them.