Noon run done.  Got in 3 miles in a slow for me time of 30 minutes.

Interesting that running up hill caused no discomfort, and only mild pain downhill - it's running on flat surface that causes the most pain.

And I can mostly isolate the pain point - it is right where the hamstring and the glute come together under the left butt cheek (TMI?).

 

Plan will now be to see if the discomfort is greater, lesser, or equal before tomorrow noon.  If same or less, I'll run.  If more, I'll rest for a couple days and hit the dreaded elliptical.

I had a very similar pain last year. For me it was caused specifically by overstriding and pushing hard uphill.  Took a long time to go away and mostly the correction happened after I started working with my coach and doing form corrections and core/ hip strengthening.

Of course, being like most hard headed runners, I probably should have stopped.  I kinda got used too it and forgot about it during the intensity of last summers training and realized some time later that it was gone.