Note that agony is suffering that one experiences, specifically strong mental or physical pain/duress - while sorrow would be the sympathy felt by others due to seeing someone else's agony. So piling on the agony would not work but piling on the sorrow would.
A well known idiom is to play the race card - meaning to accuse someone of racism--or try to present oneself as though such an accusation could happen--as a move towards personal, economic, or political gain.
Adapting this idiom to other things besides race works - so, you can say play the sympathy card or victim card as @P. E. Dant suggests in the comments. The Google Ngram on the phrases is interesting, while race is the most common, sympathy and victim are not unheard of and the idiom itself is well known and common enough that adaptations come through loud and clear with the meaning.
A less harsh term would be pulling at my heartstrings, which doesn't have a strong implication that the person doing so is trying to manipulate you.
The passive form of She played the sympathy card, for example, would be The sympathy card was played by her.