Are pKa values of acid and conjugate base the same?
Let consider the case of the phosphoric acid.

The phosphoric acid $\ce{H3PO4}$ has $pK_\mathrm{a1}$.
Its conjugate base $\ce{H2PO4-}$ has $pK_\mathrm{b1} = 14- pK_\mathrm{a1}$.

But as $\ce{H2PO4-}$  is at the same time a ( weaker ) acid as well,
it has its own acidity constant $pK_\mathrm{a2}$ independent  on $pK_\mathrm{a1}$ and $pK_\mathrm{b1}$.

Generally, acids like $\ce{HA-}$ have $pK_\mathrm{a2}$ and $pK_\mathrm{b1}$ values.
The former associated with $\ce{HA- &lt;=&gt; H+ + A^2-}$,
the latter associated with $\ce{HA- + H2O &lt;=&gt; H2A + OH-}$