I know that drugs react react to chemical imbalances, such as antidepressants increasing low dopamine levels, but I recently had some problems with my jaw. My mouth would not open to its fullest extent and so made eating a bit of a pain. I went to have it checked out and was told that I had an inflammed ligament. I was prescribed Dicoflex (Diclofenac Sodium). It got me wondering, how can this oral pill have an effect on my jaw ligament only? Does it only react with the certain conditions present in an inflammed ligament or does it have effects on ligaments all over my body, inflammed or not? Also, does the same also go for drugs for other conditions, e.g. does aspirin or parcetamol only cure your headache or does it affect other body parts?