We all have days where we feel achy or sore. But chronic, persistent pain isn’t something you should write off as a side effect of aging or over-exercising. Back pain, pelvic or abdominal pain and even what seems like a run-of-the mill stomachache or indigestion can signal many different types of cancer, from liver, pancreatic and breast to ovarian, endometrial and colorectal. If you can’t find a plausible cause for the pain you’re feeling, and if it continues to dog you, talk to a doctor.