Frequent Nose Bleeding, Headache. What Is The Problem? How To Get Cured?

My 5 year old son, has always had frequent nose bleeds ....recently he has started to get very frequent headaches , almost every day. not always but sometimes when he has a nose bleed the 1st thing out of his mouth will be his head hurts the second is his nose is bleeding . the nose bleeds done always come with a headache, but are starting to more frequently! i have mentions the headaches to his dr a few times, but they never seemed to concerned, i understand that nosebleeds are common with children, but im started to get worried, any idea what could be happening