What Does Recurrent Painful Lump Behind The Knee Suggest?

I have a golf ball sized lump behind my knee that causes significant pain and flares up after any activity, especially exercise. It fits the profile of a Baker s cyst. I underwent Graston therapy (years ago) and the professional performed Graston over this lump (unknown at the time what the lump was) and eventually disappeared after several sessions. It reappeared with same symptoms as stated above. Does this still sound like it fits the profile of a Baker s cyst?