Why does my nose run when I participate in physical activity such as cycling?

I am always a nose blower and one of my friends thinks it's a nervous habit, lol. I know it's not! When I cycle in all weathers, it gets worse as I'm always a bit snuffly or bunged up. It runs so much that I have to swallow it and have regular runny breaks - sorry if I sound disgusting! on occasions when I have finished physical activity, I sneeze and have a sore throat. I do notice that a gland on the back of my neck is swollen. Can this be an allergy?