Upper Hamstring - at connection to pelvis. "Runner's Butt" or 'high hamstring tendonopathy"
Been around for a while, but on 3/5/13, had shooting pain (day after a great speed workout), which caused me to stop a run.
PT is focusing on stretching & strengthening Hams, Hips & Core.
(increased level to 4 - out for season: that is, no racing in spring or summer at the very least)
Turned off 3/1/14 - still weak, not able to race, pain if I push distance, frequency or speed, but I can do a decent pace for 6 miles.
Proper PT (went to a very good one after 1/2 year of little progress). For a very very long time. Don't push injuries when they start sneaking their way in - I just ignored it, and then it got me the day after speedwork.