Squirmy baby

My baby is almost 3 months old and can’t ever sit still. Whenever she is being held or laying flat, anything she just is constantly moving.kicking her feet moving her arms and hands and just kinda squirming her whole body. Nothing drastic most of the time but not sitting still even though she seems content. She is most content when I am holding her upright in standing position . At times (mostly after she eats) she pulls we legs in and kicks them out and seems in pain, but only after she eats. Any advice??