  The combination of relativistic kinematics together with Coulomb or Yukawa
potentials is a common place in atomic, nuclear and meson mass phenomenology.
In meson spectroscopy, linear and Coulomb-like potentials are the most commonly
used potentials and decays rates are also calculated using the value of the
wavefunction at the origin. But, it has been known for sometime that the use of
relativistic kinematics together with Coulomb or Coulomb-like potentials
produces wavefunction singularity at the origin for S-wave
\cite{DuranFriarPolyzou}. Therefore, there is a need to address this problem
somehow. In this letter, we show how to overcome this problem without
destroying the phenomenological success of the use of relativistic kinematics
in meson mass spectroscopy. Our method can be easily implemented for similar
problems in atomic, nuclear and particle phenomenology.
