I need help with daughters unexplained illness?

She is three and has had chronic constipation since 3 months, she is on medication to help her poop. Now she has been having fevers of 102 or more almost everyday with stomach pain, it’s been going on for three weeks and when we giver her tylenol her fever subsides along with the stomach pain but the fever comes back the next day with more stomach pain, but she’s pooping fine, and does not have any urinary problems. Her pediatrition is stumped… any suggestions?