The phrase "in pain" refers to a very uncomfortable feeling that can be physical or emotional. There are several synonyms that can be used to describe this sensation. Some common options include agony, suffering, distress, discomfort, ache, pinch, hurt, throb, and twinge. Each of these phrases has a slightly different nuance and can be used in varying contexts. For example, "agony" may be used to describe intense and prolonged pain while "hurt" may be more appropriate for a milder discomfort. Synonyms can help to add variety and emphasis to writing and communication when describing feelings of pain.