How Should Foot Pain Be Treated?

I went running on Sept. 7, 2010, and 5 min of that run was on a slope. My right foot was on flat ground, but my left was on the slanted ground, and it felt very uncomfortable. That evening, I began to get pain in my left foot, only in the heel area. On a scale of 1-10, 10 being the highest, I would rate the pain at varying from 2-7. I rested for two weeks, no serious exercise, but continued regular daily activity, and took up exercising again this past week. The pain persisted off and on the first two weeks. This past week, the pain was only present after running. I run in the mornings, and the pain appears in the late afternoon and is gone by the following morning. Should I rest my foot more? I've tried ben-gay, which does seem to give some relief. Is there something else I should be doing?