pangs of conscience; remorse; guilty conscience
A fixed expression referring to the sharp, painful feeling of guilt or regret over one's actions. Often used in formal or literary contexts.
Unable to bear the pangs of conscience, he turned himself in.
Even while feeling remorse, he kept on lying.
良心 means 'conscience' in general, while 良心の呵責 specifically refers to the painful feeling of guilt or remorse arising from one's conscience.
呵責 by itself means 'torture' or 'torment', but it is rarely used alone; it appears mainly in the compound 良心の呵責.
Compound of 良心 (conscience) + の (possessive particle) + 呵責 (torment, blame). The term 呵責 originally referred to severe blame or torture, and here it metaphorically describes the torment of a guilty conscience.