The term 'BE A PAIN' can be broken down into three crossword solutions: NAG (3 letters), IRK (3 letters), and PESTER (6 letters). NAG means to constantly and persistently ask for something, usually in an annoying way. IRK means to irritate or annoy someone. PESTER means to bother or harass someone with persistent requests or criticism. All three words are used to describe someone who is a nuisance or a bother to others.