Electromagnetic forces also obey an inverse square law. It's the exact same equation as Newton's Law of Gravity, just with the letters changed.
Compare this F_g = GMm/r^2 to this F_q = KQq/r^2. The only difference is the letters, which are variables.

More importantly, notice that when you divide one by the other, the r^2 parts cancel out. Thus the relative strength is not a function of the distance between the 2 particles of masses M and m and charges Q and q.

The strong force is much more complicated, but we find again that it dominates gravity on small scales.


As for the singularities (infinities) at the location of the particle, remember that the universe doesn't allow the position of a particle to be exactly defined. So over any measurement's time scale, we'll see a "smearing out" of the charge/field/force created.


There is no complete string hypothesis that describes the whole of QM. String hypotheses only match known physics where the creators of that hypothesis have literally forced it to be the same. That's all well and good, but no verifiable predictions have been made where they can't be forced to be the same. If you add enough terms to a polynomial, you can exactly fit any data set, but that doesn't make the polynomial physics. If you can't understand what each variable is in physical terms, then you can't trust anything about it. Just adding terms and forcing compliance is fine and all, but if doing so doesn't actually add *anything* to the field of study, then ... it's not anything. Maybe someday there will be a string theory, but there simply aren't anything but bad guesses that yield no new science thus far.