Jorge,
  It’s good to see you know what your limitations are with mobility and technique.  While you are working on fixing technical issues I would look into doing the couch stretch and smashing the quads.  Simply put, the anterior hip all connects into the patella/quad tendon which is anchored on the tibial tuberosity (Osgood bump).  It you get the anterior hip to open up it should relieve the tension on the bump some.

So in summary, continue focusing on technique and overall mobility, but put some extra work into the anterior hip in the form of the couch stretch (and other anterior hip stretches) and smashing.  My favorite for smashing is barbell smashing the quad at night while winding down in front of the tv.  Also, look at your squat technique and make sure you are breaking at the hips first.  This will help keep the patella tendon from being tacked down first and taking the brunt of load in the squat.  Also, keep the shins as vertical as possible.  This will help keep tension off the knee and into the hips.

If you have anymore questions please ask.  Good luck.