Heel Pain- Can't figure out why.

I am hoping you can help me here. I've been having heel pain as long and I can't remember when it started, it was probably during my teen years, I am 20 now.
My heels have been hurting. It's really bad when I stand too long, and I can feel them throbbing. I don't seem to have the symptoms of plantar faciatitis, or any other foot problems that are common (I looked this up in a library). Could heel pain be caused by weak muscles? I noticed my feet fall in a little bit, and I had a "minor" problem with weak muscles when I was little. I know being overweight can also cause foot pain, but I am not.

I have minimal insurance also, so if you can suggest anything at home, that would be wonderful. I am not asking for a diagnosis, just a little directon.
Thank you very much.