Heal pain, what can it be?

I have been having quite a bit of pain in my right heal. deep down in side. If i rub it, its not really sore, but when I get up after sitting or sleeping, it hurts so bad that I limp for about the first 10 minutes. Then it seems to kinda fade away. if I sit for 10 -15 more minutes and stand back up it comes rite back, not as severe, but still very painful, I walk it off and then go on. this has just kinda come up in the last few weeks. A few weeks ago, I was working about 4 feet off the ground, and I did haft to jump off several times, but I don't remember any sudden shock when I landed. There are no bruises or marks.