Very fussy baby

Hi group new parents here and haven't been around a lot of babies. my baby is about to turn four months and she seems to be extra fussy at any given moment. I'm not sure what to do. Dr. Says she's healthy and just going through her fussy stage. She can be giggling and happy to crying at the top of her lungs at any given point. We check to make sure she has anything she needs but she still seems to be fussy afterwords. Please help is there something more we should be concerned about or is this normal baby behavior ?