My nose runs anytime there is any slight temp change or if i eat, why does this always happen?

It's natural: This is a form of vasomotor rhinitis and a high percentage of people suffer from it. It's more of a nuisance than a disease, but for many people it can be mildly debilitating. If you feel you must treat it, intranasal topical steroids often work well, even at very low doses. Otherwise, take advantage of those free kleenex you find in the ski lift lines! that's what they're there for.

Not allergies: This is a reflex that occurs in some people. Your nasal lining and glands are reacting abnormally. In some this is due to vascular dysfunction. To treat, avoid all irritants, especially smoke, rinse nose with saline often, exercise often and use a prescribed nasal steroid spray if needed.