My Two Year Old Grandson Was Running A High Temperature,

My two year old grandson was running a high temperature, it went as high as 104. He was having small bms. I gave him a suppository. This was Monday, he had for a bm but none since then. His fever is not as high but now he screams at noises he is accustomed too.....dog barks, fire truck sirens etc. he is now on antibiotic and is getting Tylenol and Advil.
Why is he screaming at these noises? Are the symptoms related?