Does cancer always cause pain?

No. The National Cancer Institute says that cancer often does not cause pain.

That is a good reason not to wait for pain before you see a doctor. If you have symptoms that last a couple of weeks, see a doctor, so that problems can be found and treated as early as possible.

Cancer can cause many symptoms besides pain, and most of the time such symptoms turn out to be caused by illness, injury, benign tumors, or other problems. Symptoms cancer may cause include a lump or firm feeling in the breast or under the arm, and trouble or pain when you urinate. Others are bleeding or bruising with no clear cause, changes in bowel habits, and a cough or hoarseness that does not go away. Severe fatigue that lasts, fever or night sweats for no known reason, skin changes such as a new or changing mole, and unexplained weight gain or loss are on the list as well.

Because pain is not a reliable early warning sign, the safest approach is to see a doctor about any symptom that lasts. A health care team can check the symptom and advise on next steps.