I have a strange pop in my right jaw joint that comes and goes. What might it be?

There are many types of TMJ disorders and that is exactly what you have. It is very common but unfortunately there is not much that can be done for it. You can ask your dentist for a mouthgaurd, only if grinding at night is the cause. Chewing gum can make this worse and so can tension in your jaw from stress. If it gets really bad the dentist can attempt to adjust your bite and therefore your jaw joint but this is only done in extreme situations. Other than the occasional discomfort this condition is not something that you need to worry too much about but it can get worse over time. Hope this helps!