Well, my left hamstring, which has been singing to me for a couple of weeks, is now toast.
On the run last night, I ripped/injured it severely.
I'm blaming myself. I should have run by myself, at my own pace. I think I needed more time off, after my last run. During the trail marathon last Saturday, it hurt for about 1-1/2 hours, then subsided.
Now it definitely gets some time to heal.