Is mass the one and only thing that produces a gravitional force???
No. And current theory, unconfirmed by not finding the elusive Higgs boson (you can read about that), predicts that this strange boson is what makes some particles have what we call mass, otherwise, they would only have energy.
Now, you need to know what you studied about "gravitational force" as described by Newton, has been modified by Einstein in the General Theory. Einstein theorized that gravitational force was not a force at all, but rather what we observe when space-time is bent. He postulized that space-time was altered by what we see as mass.
http://www.aei.mpg.de/einsteinOnline/en/elementary/generalRT/GeomGravity/index.html
So, it is clearly not as simple as you would like. Newtons answer is yes, but it is certainly a greater question.