D.M.
I am first time mom as well. You have to take him to a regular pediatrician. It can be nothing but it can be as well something serious..you do not want to miss it and than regret it. Do not underestimate it. It is better to deal with small thing than later with much bigger problem.There is not enough calls/visits to pediatricians !!! They are here for you !
When my son started to have crying for no reason we first thought he is having nightmares..we waited 2 weeks before we took him to a doc!well it turned out he had bad ear infection and he was given antibiotics. It was over in 5 days.