When Hamlet refers to the "pangs of dispriz’d love", he means heartache.
When Hamlet says "pangs of dispriz’d love", he refers to the pangs of unrequited love, that is to say love that is not reciprocated and causes emotional pain in the lover. The word 'pangs' is a noun and it makes reference to a brief but sharp pain. In that way, the pangs of unrequited love can be considered a heartache, an emotional grief that can be triggered by the rejection of someone loved.
