I have done a fair few 11ks over this year btw, just not kept those up.
This has definitely made the hamstring a little sore (felt it a little at this mornings Park Run).
I suspect a anything longer (15k to half marathon would really push it).
The physio had a good look and feel but the only time the pain at the back of the knee is when I bend the leg (like squatting, kneeling and sitting back and it's pretty painful.
Nothing visual to go on, so a tear does sound possible but all seems linked to that initial hamstring injury.
Hopefully the scan will give more details.