I feel your frustration and i understand you racking your brain trying to figure out the whys and hows. DD had her immunisations also but i never put any of her discomfort down to this as i'd not heard of the link before. BB has taught me another useful tip As Sargres above has said we also peaked around the 7 week mark. At first she was occasionally uncomfortable, every second night may have been a bit of a struggle to get to the end of the 'witching hour' but i think it was either week 6 or 7 where every single night we had screaming, arching of her back, one exhausted little bub who was just too uncomfortable to sleep, the list goes on.... until she finally would fall asleep about the 11pm mark for a reasonable nights feed/sleep routine. We too were on medication (zantac) somewhere between 7-8 weeks and it made a difference and it helped ease the symptoms.

So i can't help by saying it'll ease off or not because i really don't know. Each little ones case of 'reflux' (i believe they can all have it, it just varies in severities) is difference and as to if your little mans is mainly due to the immunisation i'm not sure how you'll be able to tell. I suppose time will tell, in the mean time you just do what you can do to help your little one through their discomfort.

Good luck