I have swelling in my right thigh. it's not painful just swollen. is it possible that i have a blood clot or cancer?

Thigh swelling: Low probability at your age, but needs to be worked up, see your doctor.

Depends: Usually a deep venous thrombosis (clot) on the legs are in the calf, but occasionally can be seen above the knee. They are usually tender or painful. There are many causes of swelling in the lower extremities, but a DVT is a valid concern, especially if you're on birth control pills. See your doctor for an evaluation.