I am no authority on running, since all the running that I did in my younger days sounds very much like you. Since my resurfacing, I have gotten back into doing a lot of running around the tennis court, and a little bit on the trails; not exactly long distance, but lots of sprinting.
With that in mind, I have two thoughts to share with you based on that experience.
I switched to Nike "Dual Fusion" shoes, and they have made a huge difference. They have a very soft and flexible sole, but still with plenty of cushion to absorb impact. The heel is not quite as built up as in some running shoes, and I found that this also provided less heel impact. I have used them for tennis and the little bit of trail running that I do, and found them to have vastly less impact, especially in the heel, than any of my other running shoes. I know that the marathon guys would not approve of these shoes, but for the distances that you and I are running, you might just try them on in the store and see if you get the "wow" reaction that I did. It is about the only shoe that I wear now.
The pain you are describing sounds like something that I dealt with occasionally for the first year or two. Is it tender when you press on the greater trochanter? If so, it could be trochanteric bursitis which is what I had. Like you, I found the best relief was to use the foam roller on the IT band which puts pressure on this bursa if it is tight.
Great to hear that you are getting back into running; another case of resurfacing giving us our lives back.