This sensation is called Formication. Why you are experiencing it, I am not sure. It can occur with menopause, herpes zoster infection, fever, some medications, alcohol withdrawal, anxiety, etc.
You can seek the opinion of an Allergist to rule out if this is allergy-related and go from there.
Meanwhile, you can try OTC Benadryl or an anti-histamine to see if that helps.
maybe it is body lice. u may not notice them during the day because u r way more active.
Look up Magellons Disease on Utube. Tons of people have it but there is much info on Utube about it. Also, it could be muscles and the nerve bundles within them or lower back problems. If you slowly stretch very slowly sitting trying to reach for toes and after wards you get that feeling then it is the nerves within the muscles that have not been stretched out enough. Be gentle.
This sounds like what is wrong with me but i read something about parasites in the body r the skin on the internet has the same symptons.