It my hamstring- way up high where it ends at my butt- whatever that connection is called.
It took a while before I could even try running- a few months, then compensation injuries started.
Maybe because of age, I really struggled to run more than 3 miles. I just retired form teaching and admit that the pandemic really hit me- teaching was TOUGH, tougher than you can imagine and I'm in a great school in one of the top education states in the country.
I'm finally back to feeling comfortable with 4-5 miles a day.