The heel of my foot hurts when I walk, what should I do?

Every time I try walking, my right heel hurts. (Only my right heel and only my heel) The pain is bearable, but I usually limp. It almost feels like I'm pressing on a bruise, but there's no bruise. My parents said it was lack of exercise, but I walk a mile or so everyday. I thought the pain would wear off, but its been a couple days. I also have to go camping/hiking in 2 days. Please help!