The term POST-WORKOUT FEELING can be summarized by two crossword solutions: ACHE (4 letters) and SORENESS (8 letters). ACHE is a general term for pain, usually localized in one area of the body. It can range from mild to severe and can be caused by a variety of factors, including physical activity. SORENESS is a feeling of tenderness or discomfort in the muscles after exercise. It is usually caused by the buildup of lactic acid in the muscles during exercise, which can cause inflammation and pain.