Could this be it!?
Good news! I think I finally got to the bottom of things and found my problem. Had a successful 5K run this morning (1k splits) 4:05, 4:08, 4:12, 4:08 and 4:06 and finished off with a 3:35 1K just because I could. As I was able to stride out and do it with no pain I was almost dizzy with happiness. It has been giving me trouble while sitting at work today but I really think I'm on the way to getting rid of it.
While the pain was coming from what I thought was the gluteus maximus, it was in fact more in the area of the of gluteus medius, or closer to the gluteus minimus and the pain was radiating from "Trigger points" here down my left leg!
Thank you all for your advice last post it all led me to this find, be it indirectly or directly.
On Ricks advice I looked up "Trigger Point Therapy" and Marty Recommended the book "The Trigger Point Therapy Workbook" that I ordered and have already been working with for a few days now.
Now I don't want to give this methodology the full seal of approval just yet but I'm so impressed with my present condition vis~a~vis last week, I'm almost ready to shout its praises from the highest mountain. Just need a few more sessions to be able to get up that mountain to do it ;)
Thanks again all, I'll write more on this later in the week.