For the last few years I have had an excess amount of mucus/snot in the back of my nose. I can easily transfer the mucus from the back of my nose to my mouth by performing a contractile motion with my nose/throat muscles. Once I spit out the mucus, it usually comes back in about 5-10 minutes. Moreover, it happens whereever I am at, so I don't think it is because of allergies. Help!