Basically what has already been said. I mention anything that is abnormal for me. Anything that seems off, I'll mention it. Obviously, if I just feel sick etc, I won't go to the doctors unless it lasts for a week or two and is uncomfortable/causing me pain.
You should generally go for anything that causes you pain/discomfort.
A good rule is to wait it out for a few weeks, if the symptoms are still present after that time with no sign of improvement, or they are getting progressively worse, then it's probably a good idea to see a doctor.