We investigate the photon-drag shift current in an isotropic single-valley two-dimensional massive chiral Dirac model with chirality index $J$ by directly evaluating the full finite-$q$ non-vertical response beyond the perturbative small-$q$ regime. % Our central result is that chirality qualitatively reorganizes the sign topology of the finite-$q$ photocurrent $\vec{j}(\vec{q})$. % For $J=1$, the photocurrent remains broadly positive, whereas higher-chirality sectors ($J\ge 2$) generically develop internal zero-current contours and sign reversals within the kinematically allowed region. % We further show that the photocurrent is symmetry-constrained to be purely transverse, $𝐣(𝐪)\propto \widehat{𝐳}\times 𝐪$, and vanishes in the strictly vertical-transition limit $q=0$ in centrosymmetric systems. % Pauli blocking further shapes the response by selecting the active portion of the resonance contour, while its extinction at large () or (q) follows from a simple kinematic cutoff. % These results establish the isotropic massive chiral Dirac problem as a symmetry-controlled benchmark for chirality-dependent finite-$q$ shift currents.