Thank you for your query at DoctorSpring.com
I have read your question with diligence .
It looks from. Your report that you are having partial rupture of your tendoachillis at and near its insertion .
At your age you should not take chance in conservative treatment, as there are decrease healing processes. Surgery will help in inducing good and sound healing in good hands.
My opinion is towards the surgery side as there are increase chances that you may have relief from pain.
Hope this will help you.