I'll second hunter4623 on the plantar fasciitis. I didn't know what it was earlier this year and kept training hard. I thought I had a badly bruised heel. I ended up with a ruptured plantar fascia. If I'd have known what it was there was a lot that could have been done to treat it and I'd not ended up rupturing it....but if you're not training really hard it's probably not going to rupture on you.
