朦胧得想念是痛苦
[méng lóng dé xiăng niàn shì tòng kŭ]
'Vague Memories Bring Pain'. There's some pain in recalling blurry old memories or experiences that aren't clear, often suggesting there was something left uncompleted, leading one's memory lingers and haunts them. That makes it particularly painful when these past fragments occasionally float up to present mind randomly.