The pent-up feelings in his chest finally poured out in a poem.
Tips
usage
抑塞 is literary and uncommon in modern speech — the everyday word for 'depressed / gloomy' is 郁闷 (yùmèn) or 压抑 (yāyì). 抑塞 specifically captures a feeling of being internally stifled or pent up, as if something can't get out; you'll mostly see it in classical poetry and literary prose.
mistakes
塞 has three readings — sāi (to plug, everyday), sài (frontier fortress, as in 塞翁失马), sè (literary 'to block / stifle'). In 抑塞 it's sè, the literary reading. Reading it as yì-sāi will sound off.