I noticed my son had tiny lumps on his neck/head area, about 1.5 inches behind his ear. I first noticed this when he was 6 weeks old, I brought it up at his 8 week immunisations and the doctor said they were lymph nodes, the doctor said they might be swollen because he has cradle cap (which he doesn’t) or he’s had a recent cold. He’s 5 months old now and these lumps fluctuate in size almost every day, some days I really struggle to find them because they are almost non-existent, other days they are more prominent. They are never bigger than pea sized, however. 
I find it concerning how it’s been 4 months and they are still there. He isn’t unwell or anything. I took him back to the doctors a few days ago and the doctor said she thinks it’s the bones in his skull that I’m feeling (definitely not - bones don’t shrink then get bigger again!) she made a referral to the ultrasound department at the hospital anyway, and they rejected the referral. 
Well, today I noticed he also has one further up on his scalp. It wasn’t there before.I  googled lymph node locations and the lymph nodes that are swollen on my son are the occipital lymph nodes. I haven’t noticed them swollen on any other area of his body, but I really wish a medical professional would just check him over. 

the worst case scenario keeps coming into my mind , hence why I’m here. I know it’s probably nothing. But I’d love opinions if anybody has experienced this with their baby and what the outcome was.