What Causes Fainting Spell With Dizziness And Chest Pain?

My husband recently fainted 2 days ago. We don t know then reason why and he doesn t remember fainting. He only knows because I saw it happen. Since then he s been really sleepy and complaining of pain in his chest, weakness, and dizziness. He also hasn t ate much. I m just wondering if there is something serious going on. He did hit his head pretty hard.