ます

My purpose is to suggest a cure for the ordinary day-to-day unhappiness from which most people in civilized countries suffer, and which is all the more unbearable because, having no obvious external cause, it appears inescapable.
上の英文について質問です。whichの前の fromは、suffer fromから来た、いわゆる「in which」の構文と同じ物という解釈で合っていますか？