This is the 7th verse of Ghalib’s 2oth ghazal.
Gham agar-che jaN-gusal hai, pe kahaN bacheN ke, dil hai
though agony corrodes and melts heart, heart can’t remain without it
Gham-e-ishq gar na hota, gham-e-rozgar hota
If there were no love agony in my heart, it would have been filled with headaches of mundane matters.
JaN-gusal= soul melting Gham-e-Ishq= anguish suffered o in love gham-e-rozgar=pain and hardship suffered in day-to-day struggle to make both ends meet.
Meaning: Anguish is anguish; may be of love or livelihood. Ghalib says heart is a vessel holding agony; it is never empty. He says though agony is caustic, my heart loves it. I therefore can’t be ever free from pain and sorrows. If I were not smitten by love, issues of daily livelihood would have pained me. In comparison, I find better to have pain of love rather than having headaches of livelihood. I am happy, I have just one pain; the pain of love.
Finer aspects: Heart is a cup that always remains filled with blood; it can never be without it. Ghalib has expanded this fact saying heart always remains filled by agony and cannot be empty of it