Pain in the rear is a colloquial term used to describe an annoying or difficult situation. The crossword solutions for this term are PEST (4 letters), HASSLE (6 letters), and SCIATICA (8 letters). PEST refers to an irritating person or thing that causes trouble. A HASSLE is a difficult, time-consuming, or annoying task. Sciatica is a medical condition characterized by pain in the lower back, buttocks, and legs.