My fully BF little guy was constipated. He would go a week to 10 days between each time and was beside himself by the end of this, each time. And like you, I was told it wasn't an issue.
Turned out he was dairy intolerant. After 6 weeks off dairy for me, (he needed time for his gut to fully heal from all the inflammation that was caused) and some probiotics for us both, things went back to normal and I had a much happier, more settled little baby.