I would like to thank each of you for your input! Lots of great information and personal anecdotes.
This morning, I went to my chiro, who is a sports trainer as well, and explained the pain to him. I told him I was pain free since I stopped hiking Saturday...He had me lay on a table, and pushed on a spot, and I almost came off the table..lol Apparently, not pain free at all. Anyway he manipulated it a bunch of different ways, used a roller, etc, and then iced it with stim. I am going back tomorrow for more treatment. He said it was definitely my IT Band, and attributed it a lot to a lack of support for the lateral longitudinal arch in my left foot, so that it remained more stable. He also said it sounded like I did too much steep downhill hiking on my first two trips, and my legs were not in condition for that after so much time off during my CPA busy season. Anyway, I will try to pry more info out of him tomorrow about what he recommends other than shoes with better support. I am going to take my boots tomorrow for him to see. They are Oboz Yellowstones, with the stock insert, but also have an extra insole that a guy at REI put in for me to make the boots fit tighter (I bought a half size too big at another outfitter, and they were a little loose).
I am definitely going to incorporate some of the above suggestions about strengthening, stretching, and foam rolling my legs. I am also going to try to change some of my upcoming trips to be a little less brutal as far as elevation change over short distances goes. We have a trip on the first weekend in June to hike Tinker Cliffs and McAfee knob North to South, and that has a pretty steep downhill from McAfee Knob to the Catawba parking lot, so I may cancel that trip.