How can you become addicted to painkiller pills?

Which medicine? Opiate pain relievers frequently cause physical dependence. The difference between dependence and addiction is often confusing. Dependence means that if you stop the medication abruptly, you'll have withdrawal symptoms. Often this is nausea, diarrhea, sweating, misery, and is temporary. Addiction is a psychiatric diagnosis and, although similar has different meanings.
Addicited. Using the meds in a manner not prescribed. Also using them when you do not need them.