Listen to All In My Head (Flex) (Originally Performed By Fifth Harmony Feat. Fetty Wap) online. All In My Head (Flex) (Originally Performed By Fifth Harmony Feat. Fetty Wap) is an English language song and is sung by Sunfly Karaoke. All In My Head (Flex) (Originally Performed By Fifth Harmony Feat. Fetty Wap), from the album Sunfly Hits, Vol.367, was released in the year 2016. The duration of the song is 3:26. Download English songs online from JioSaavn.