Hi. Greetings. This could be a sign of dermatological or neurological or psychiatric disorder. Firstly see a dermatologist to rule out any actual infestation of your body by organisms. Make sure your bed is free of bugs. Use a moisturiser, dry skin aggravates such sensations. If all this is fine and symptoms continue, then you may have to meet doctors of others specialty as mentioned above for their expert opinion. Hope this helps. Warm regards.