I'd also recommending having the pediatrician look at them, but I wouldn't wait until the next appointment not knowing what they are. If they are lymph nodes, they'd certainly be tender and uncomfortable for her when you touch them (if she's fighting an infection of some sort).
My kinds never had anything like that, but when I found a knot on my collarbone, I'm glad I followed my instancts and had them checked because my situation was serious (even though most people dismissed it as part of being postpartum).
Instead of Google, I'd recommend either HealthyChildren.org (parenting website from the American Academy of Pediatrics), MayoClinic.com or WebMD.com to see if that can provide any helpful possibilities. Regardless, I'd call the pediatrician and let them be the ones to decide if they need you to bring him in or not.
Just a quick note on lymph nodes - they're not all harmless. 95% of swollen nodes are normal infection-fighting causes. In my case, the small, pea-sized node on my collarbone that didn't hurt was cancer. Whenever nodes are involved, always have them checked out.