  In this work, we investigate the relativistic quantum dynamics of spin-0
massive charged particles in a 4D curved space-time, the generalization of a
cosmic string space-time. We investigate the Klein-Gordon equation in the
presence of external fields in the considered framework. We also investigate a
quantum particle described by the Klein-Gordon oscillator in the curved
background space-time in the presence of external fields. We see that the
energy eigenvalues get modifies in comparison to the results obtained in a
cosmic string space-time.
