Every time i wake up, i always have sort of runny nose. is it allergy?

Maybe, maybe not: Allergies can cause this, esp. If you are allergic to something like dust mites, which can live on our pillows and mattresses. If allergic, you'll usually have itchy eyes, sneezing, etc., as well. Nasal irritants (like smoke, perfumes, chemicals, etc.) can also cause this, but lack the itching & sneezing. There are some rarer causes as well. See your primary doc or an allergist for more info.