Clicking or popping is a symptom of TMJ. When this first happened to me (on one side) I just ignored it but over time it got worse and worse meaning my bones were eventually rubbing together and I began to have headaches, ringing, dizziness,etc. No need to worry. if you do have TMJ then its probably in the early stages I'd just have it checked out the earlier the better
Your joint is obviously out of place when it clicks this can be due to a variety of factors such as: teeth grinding, injury, being double-jointed, etc.,