Dear Ms Bharathi,
One has to make sure that the disease is under control ; I'm sure u r under supervision of an Oncologist. This doctor, who has evaluated U will be the best person to decide what pain killer would suit you. It is in fact, his normal duty to see that U r pain free.
One of the simplest and safest pain killers is paracetamol in a dosage of 650 to 1000 mgs; but do check with your doctor.
Good Luck,
Dr. M.Mohan Rao, Chennai, India.
Visit : http://www.mohanraohospital.com