There are several terms that are important to understand related to taking opioid pain medications (medicines like vicodin, norco, oxycodone, morphine, etc ) on a long-term basis for a chronic pain condition.
Dependence refers to a physiologic response of cell receptors when being exposed to a medication over an extended period of time. This is not addiction.
Tolerance can develop over time, which necessitates having to use more of the medication to get the same effect. This is not addiction.
Withdrawal symptoms can occur if the cell receptors suddenly are without the medication, because there are receptors throughout the body that are used to receiving the medication. So if a patient is taking a significant amount of an opioid and suddenly stops, symptoms such as tremors, gastric upset, diarrhea, nausea, sweating, etc, could occur because the cells though out the body are not receiving the medication as they are used to. This is not addiction.
Addiction is the psychologic need to have a drug. It can also apply to behavior, such as shopping, the internet, eating or drinking, etc, to soothe the emotions and the psyche. A person who is addicted to a drug may develop dependence and tolerance and go through withdrawal if the drug is stopped suddenly, but these are normal physiologic responses to stopping the drug. It is the psychologic and emotional effects of not having the drug (or behavior) for the addict that are the most difficult to stop. This often will lead to behavior to obtain the drug (or substitute behavior) even if that behavior will cause harm to the patient and loved ones, i.e. forging prescriptions, stealing to get money or drugs, being secretive, hoarding, etc.
If you feel that you are becoming addicted to the vicodin, speak with your doctor about this. Be honest and forthright so that your situation can be appropriately evaluated and the appropriate advice can be given for your best care.