When I was working with infants, one of the baby's had something similar, and I was told that it was a sign of some kind of nutritional deficiency--nothing that would hurt him short term, but something to look into and correct for the long term.
Get as much info as you can before heading to the doctor. Maybe google the symptoms. Caring for baby is a team effort. Doctors are still learning, too; they just have a bigger head start. They know based on what they've seen before. Parents bring a different perspective, an individual case. Both perspectives are equally valuable.
I was misdiagnosed based on one doctor's experience and the fact that a particular medicine seemed to help. It took my familiarity with my own body and habits and my persistence and willingness to try some things on my own to get a more accurate diagnosis. Use ALL of your resources; this is NOT a dress rehearsal.