Pain in groin and left leg after hernia operation

Hello,im a fit male 20 years old.i had a sports hernia 3 years ago and had an operation in Germany,i did not have the mesh,i had it stiched right back up by specialist.i play soccer on a daily basis and i keep getting pains in my left groin right below my scar and all down the back of my left leg,and occasional lower back pain,it comes for a few weeks and then leaves for a few months then it will come back again.also lately i have had chronic pain in the back of my knee which also increases the more i run is this linked also??The pain normally increases as i play so the longer im playing the worse it gets but i feel like its a never ending cycle.I had an MRI can a few months ago but nothink appeared and the nurse simply said to me it could be scar tissue build up.but surely it has to be more??its keeping me from playing soccer,how can i solve this??